Things to check: -

1. Check the following registry key HKLM\SYSTEM\CurrentControlSet\Services\ASP.NET_1.1.4322\Performance\Library and make sure that it is pointing to correct version of aspnet_isapi.dll.
2. Shutdown IIS and remote registry services.
3. Run commands
1. unlodctr ASP.NET_1.1.4322
2. unlodctr ASP.NET
4. Then from %Framework% folder, run the following commands: -
1. lodctr aspnet_perf.ini
2. unlodctr aspnet_perf2.ini
5. After that restart IIS and remote registry services.
6. Check whether the following key exists, HKLM\SYSTEM\CurrentControlSet\Services\ASP.NET_1.1.4322\Names
7. If the machine is a Domain Controller, we should have IWAM account instead of ASPNET (NETWORK SERVICE) account in the permissions list for the above registry keys.
8. If that still doesn’t resolve the issue then we might be loosing on the required permissions. Worker process identity should have the effective permissions given below on the following registry key HKLM\SYSTEM\CurrentControlSet\Services\ASP.NET_1.1.4322\Names

1. Query Value
2. Set Value
3. Create Subkey
4. Enumerate Subkeys
5. Notify
6. Read Control

Hope that helps!!!

Parag