Cannot log in to ArcGIS Server Manager for the Microsoft .NET Framework 9.2

Description

Instructions provided below describe some of the common errors experienced while logging into ArcGIS Server Manager for the Microsoft .NET Framework. After entering a username and password, the Manager gives one of the following two error messages:

Error message 1:
"Sorry...
An error has occurred at:
http://<server_name>/ArcGIS/Manager/Default.aspx.
Object reference not set to an instance of an object.
For more details, check Manager's web server application event log."

Error message 2:
"You must enter an account that belongs to the ArcGIS Server Administration Group (agsadmin)
and has administrative privileges on the server machine."

Cause

For Error Message 1
ArcGIS Server Manager may be unable to correctly process the Windows user account password. This is a known bug with ArcGIS Server Manager and will be addressed in a future patch release. Please change the password for the Windows user account being used when logging in to ArcGIS Server Manager. See the Related Information section below for more info on how to do this.

Note:
After changing the password, please log out of Windows and then log back in to ensure the changes have taken effect.

Solution or Workaround

1. Right-click My Computer on the desktop and click 'Manage'. This opens a new window titled 'Computer Management'.
2. In the left pane, expand 'Local Users and Groups' node and click 'Group'. All the groups are listed in the right pane.
3. Verify that the user account for logging in to Manager is a member of both the Administrators and agsadmin groups. To do this, double-click the Administrator group and verify if the user is listed as a member. Repeat the same procedure for agsadmin group.
4. To add an account to these groups, it is necessary to restart IIS for the group membership to take effect.
   
   

   Note:
   Make sure to log off the machine and log back on to ensure the changes have taken effect.

   
   
5. To restart IIS, click Start > Run. In the command window, type 'iisreset'.