The above error appears, because of an incorrect path that was set on the ISAPI filters of OfficeScan or SMEX website in IIS.

To resolve this:

1. Open IIS Manager.
2. Select which site you want to configure
• For WFBS Console: Expand Sites > OfficeScan.
• For MSA Console: Expand Sites > SMEX Web Site.
3. In the middle pane, select ISAPI Filters.
4. Expand the columns as required and look for an Executable path with "\\".
5. Click Edit:
   

   From the above screenshot, change the "\\" to "\". The path will be:

   C:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_filter.dll

6. Restart the IIS service and access the WFBS or MSA console again.