This error occurs when,
- You installed SCOM full management console first
- Then you installed Web Console on a later date
- Now, you are getting this error when you visit SCOM web console
The issue is SCOM setup doesn’t install the following four DLL files correctly to the web console installed location. The solution is really easy.
Find the following DLL files at %Program Files%\System Center Operations Manager 2007.
Copy the above DLLs to %Program Files%\System Center Operations Manager 2007\Web Console\Bin.
I would run a IISReset command and try accessing the web console again.