I keep on getting the same error and for the life of me i cannot figure out what i am doing wrong.
I go to "C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322\Temporary ASP.NET Files and there is no \root\ file. 
Can someone please help me.
This is the error from the page.

Server Error in '/' Application. 


Access to the path "C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322\Temporary ASP.NET Files\root\3075c8b2\50ae88e3" is denied. 
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.UnauthorizedAccessException: Access to the path "C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322\Temporary ASP.NET Files\root\3075c8b2\50ae88e3" is denied. 

ASP.NET is not authorized to access the requested resource. Consider granting access rights to the resource to the ASP.NET request identity. ASP.NET has a base process identity (typically {MACHINE}\ASPNET on IIS 5 or Network Service on IIS 6) that is used if the application is not impersonating. If the application is impersonating via <identity impersonate="true"/>, the identity will be the anonymous user (typically IUSR_MACHINENAME) or the authenticated request user. 

To grant ASP.NET write access to a file, right-click the file in Explorer, choose "Properties" and select the Security tab. Click "Add" to add the appropriate user or group. Highlight the ASP.NET account, and check the boxes for the desired access.

Source Error: 





An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. 

Stack Trace: 





[UnauthorizedAccessException: Access to the path "C:\WINDOWS\Microsoft.NET\Framework\v1.1.4322\Temporary ASP.NET Files\root\3075c8b2\50ae88e3" is denied.]
   System.IO.__Error.WinIOError(Int32 errorCode, String str) +393
   System.IO.Directory.InternalCreateDirectory(String fullPath, String path) +632
   System.IO.Directory.CreateDirectory(String path) +195
   System.Web.Compilation.PreservedAssemblyEntry.DoFirstTimeInit(HttpContext context) +85
   System.Web.Compilation.PreservedAssemblyEntry.EnsureFirstTimeInit(HttpContext context) +97
   System.Web.Compilation.PreservedAssemblyEntry.GetPreservedAssemblyEntry(HttpContext context, String virtualPath, Boolean fApplicationFile) +29
   System.Web.UI.TemplateParser.GetParserCacheItemFromPreservedCompilation() +91
   System.Web.UI.TemplateParser.GetParserCacheItemInternal(Boolean fCreateIfNotFound) +148
   System.Web.UI.TemplateParser.GetParserCacheItemWithNewConfigPath() +125
   System.Web.UI.TemplateParser.GetParserCacheItem() +88
   System.Web.UI.ApplicationFileParser.GetCompiledApplicationType(String inputFile, HttpContext context, ApplicationFileParser& parser) +171
   System.Web.HttpApplicationFactory.CompileApplication(HttpContext context) +43
   System.Web.HttpApplicationFactory.Init(HttpContext context) +485
   System.Web.HttpApplicationFactory.GetApplicationInstance(HttpContext context) +170
   System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr) +414




Version Information: Microsoft .NET Framework Version:1.1.4322.2032; ASP.NET Version:1.1.4322.2032 

This is not a DNN issue.  It appears to be either an ASP.NET scriptmap problem or a permissions problem.
Is the .NET Framework properly installed and registered with IIS?
If you installed the .NET framework before IIS, you must manually register it with IIS.
aspnet_regiis.exe will update the scriptmaps for an ASP.NET application to point to the ASP.NET ISAPI version associated with it.
aspnet_regiis.exe can be found in "\Microsoft.NET\Framework\v1.1.xxxx", or via .NET Framework SDK Tools.
 

I greatly appreciate your help.
I am running Windows 2003 Server Enterprise Edition.  The .Net Framework that is required is the one that came with the OS.  As far as the permissions go i have followed the steps that are given in the install document folder and still am getting this issue.  
I tried your suggestions and am still getting the same results I am wondering if it is because of the security levels of the Enterprise edition i gave the permissions to the folders and nothing has changed.  I wonder if it would react different on Windows 2000 Standard server?
Any Suggestions

You need to manually delete the asp.net temporary file.  It's probably corrupted.
Navigate with your file explorer and delete the entire dotnetnuke directory.  If you get a message that the file is in use, kill the aspnet process using task manager (note this will interrupt all asp.net sites on the server)

Ok, I deleted the asp.net temporary file. and deleted the entire dotnetnuke directory.  now what do i do?  Do i try installing again? How would the asp.net temp file get corrupted?
 
Any further help would be much appreciated.

Ok I did a little more work after doing what you said to do.  Now i am finally getting to the DotNetNuke page but,
Upgrade Error: ERROR: Could not connect to database specified in connectionString for SqlDataProvider
it says Login Failed for "user" and i know the user account had every right under the sun.  It should have worked.
Thanks for the help to get me this far.

If you deleted the DNN directory in the tempory asp.net file, then you just browse to DNN to start.  The DNN directory in the tempory asp.net cache will auto populate by itself.
If you deleted the DNN directory in IIS (which is not my clearly stated in my recommendation because I meant the entire dnn directory in the temporart asp.net cache), yes, install again by unzipping the install files..
The aspnet temp file can ge corrupted when you interrupt the loading process of the webserver.  I see it happen when testing and debugging new modules.

Thank you for all your help.  I did as you suggested and i am getting alot closer to getting this thing up and running i think in the past 5 days i installed and uninstalled it 12 to 20 times trying to get it to work.  That and messing with another portal.
Back to my problem.  I finally got a little furthur.  the issue i am having know is that it seems that DNN and SQL 2000 aren't seeing each other fully the error i am getting now is 
Installing DotNetNuke

 



        	body {font-family:"Verdana";font-weight:normal;font-size: .7em;color:black;} 
        	p {font-family:"Verdana";font-weight:normal;color:black;margin-top: -5px}
        	b {font-family:"Verdana";font-weight:bold;color:black;margin-top: -5px}
        	H1 { font-family:"Verdana";font-weight:normal;font-size:18pt;color:red }
        	H2 { font-family:"Verdana";font-weight:normal;font-size:14pt;color:maroon }
        	pre {font-family:"Lucida Console";font-size: .9em}
        	.marker {font-weight: bold; color: black;text-decoration: none;}
        	.version {color: gray;}
        	.error {margin-bottom: 10px;}
        	.expandable { text-decoration:underline; font-weight:bold; color:navy; cursor:hand; }
        

Server Error in '/' Application. 


Object reference not set to an instance of an object. 
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error: 





An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. 

Stack Trace: 





[NullReferenceException: Object reference not set to an instance of an object.]
   DotNetNuke.Framework.Install.InstallApplcation() +47
   DotNetNuke.Framework.Install.Page_Load(Object sender, EventArgs e) +220
   System.Web.UI.Control.OnLoad(EventArgs e) +67
   System.Web.UI.Control.LoadRecursive() +35
   System.Web.UI.Page.ProcessRequestMain() +750

If you get this far, check the database and see of any DNN tables got created.  If the database is still empty, then the connection string error needs to be investigated further.  Make sure the SQL server is enabled for mixed mode security (SQL and NT).
If the DNN database has been populated with DNN stuff, then your connection string is probably good, the error message is misleading.  In this case,  it is likely that DNN does not have enough permissions on the disk drive.  The most common mistake is not granting read access to the root of the disk drive.  For example, if you install in d:/dnn3, grant read to d:/.