Error: Unable to register the DLL/OCX. The DllRegisterServer call failed
After installing ArcGIS Desktop and rebooting, the following error message displays:
Error: Error configuring ArcInfo Unable to register the DLL/OCX. The DllRegisterServer call failed.
An incompatiable version of comcat.dll.
Solution or Workaround
Warning: The instructions below include making changes to essential parts of your operating system. It is recommended that you backup your operating system and files, including the registry, before proceeding. Consult with a qualified computer systems professional, if necessary. Esri cannot guarantee results from incorrect modifications while following these instructions; therefore, use caution and proceed at your own risk.
The compatible version of comcat.dll is 4.71. To determine the version, in Windows Explorer, right-click C:\WINNT\System32\comcat.dll, click Properties, and click the Version tab.
If the version is incorrect, refer to Comcat.dll update for ArcInfo 8.0.x/ArcGIS 8.1 Windows Intel NT installation for the solution.