Windows 7: unable to register DLL - Error Code:0X80004005
According to this: http://www.vistax64.com/vista-installation-setup/33219-regsvr32-error-0x80004005.html
Run it in a elevated command prompt.
Open the start menu and type cmd into the search box
Hold Ctrl + Shift and press Enter
This runs the Command Prompt in Administrator mode.
Now type regsvr32 MyComobject.dll