Today I was getting following error while writing to Event Log on Windows 2008 Server (also applicable to windows 2003 server) using .NET

The resolution worked for me was appending (A;;0x3;;;AU) in CustomSD without quotes under HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Eventlog\EventLogName in windows registry where AU is referring to "Authenticated Users". Because in W2K3, the security of Application Event Log is controlled by CustomSD.
After appending the value would be similier to

O:BAG:SYD:(D;;0xf0007;;;AN)(D;;0xf0007;;;BG)(A;;0x f0007;;;SY)(A;;0x7;;;BA)(A;;0x7;;;SO)(A;;0x3;;;IU)(A;;0x3;;;SU)(A;;0x3;;;S-1-5-3)(A;;0x3;;;AU)


If CustomSD doesnt exists, then create a string named CustomSD and set its value to O:BAG:SYD:(A;;0x3;;;AU)

 P.S. Be careful by taking proper backup of registry before doing any change to it.

If you are getting a popup while navigating through Microsoft Dynamics CRM Application asking you to save Blank.aspx file, following workaround will help you

Please edit the default blank.aspx file in CRM (Sever where CRM is installed) so it contains data. This file is located at My Computer | System Drive | Program Files | Microsoft Dynamics CRM | CRMWeb |_ root. Here you will find the Blank.aspx text file.

Open the file and add some text to the file, for example you can add "Test" to the file (then there would be following three lines)

Test

<% Response.Expires = 1440; %>

<% Response.Cache.SetCacheability(HttpCacheability.Public); %>

Once you have added data, save the file, clear your temporary Internet Files, and do an IISreset. Once this is done go back into CRM to verify that this has resolved this issue.

If you get following exception while uploading / creating new report using Source Report Type -> Exising file

==============
[CrmException: Exception of type Microsoft.Crm.CrmException was thrown.]
  Microsoft.Crm.Application.Platform.Report.InternalCreate(String xml) +721
  Microsoft.Crm.Application.Platform.Entity.Create() +109
  Microsoft.Crm.Application.Forms.AppForm.RaiseDataEvent(FormEventId eventId) +408
  Microsoft.Crm.Application.Forms.EndUserForm.Initialize(Entity entity) +57
  Microsoft.Crm.Application.Forms.EndUserForm.Execute(Entity entity) +13
  Microsoft.Crm.Web.Tools.ReportProperty.ReportPropertyPage.ConfigureForm() +202
  Microsoft.Crm.Application.Controls.AppPage.OnPreRender(EventArgs e) +30
==============

The issue lay with our RS permissions.
In addition to failing to upload reports, we tried downloading them from CRM too. This gave us an NT permissions error.
So, we opened up (localhost)/reports, navigated to the CRM datasource (typcially 'Organization_MSCRM), then properties, then security,
and then added a user / group called NT AUTHORITY\NETWORK SERVICE,
and gave them the permissions of CRM Publisher.
After that it all worked fine.

Thanks to Lee/Ronald

If you get following exception while uploading / creating new report using Source Report Type -> Exising file

=============
Stack Trace Info: [NullReferenceException: Object reference not set to an instance of an object.]
   at Microsoft.Crm.Reporting.SRSReport.convertDataSource()
   at Microsoft.Crm.Reporting.SRSReport..ctor(String xmlContent, String originalFilter, Boolean convertReportToCrm, ExecutionContext context)
   at Microsoft.Crm.ObjectModel.ReportService.CreateInternal(IBusinessEntity entity, Boolean isScheduledReport, ExecutionContext context)
   at Microsoft.Crm.ObjectModel.ReportService.Create(IBusinessEntity entity, ExecutionContext context)
=============

The reason can be the Shared Datasource used while creating Report in Visual Studio 2005.

1. Create a new Report Project in Visual Studio 2005

2. Right click on Reports, choose to add Existing Item

3. Double Click on the report to open it.

4. Click on the Data (top tab) above the open report file.

5. Click the "..." button just to the right of Dataset to open Dataset Properties.

6. Click on the "..." button to the right of the Data Source drop down list.

7. Clear the "Use shared data source reference" option.

8. Click on the "Edit..." button to the right of Connection string.

9. Enter the correct SRS Server Name, enter the authentication method, and choose the correct database name.

10. Click OK, this will change the source for the entire report.

11. Click OK to the Visual Studio window again.

12. Choose, File, Save <Report>.

13. Try to upload it again. This time it should load.

 Thanks to mennotk