Return codes for RegServer and REGSVR32.EXE?

I am trying to make sense of the return codes when I try to register and unregister COM objects - I can't seem to find a table that lists what the return codes mean.

My application is able to register and unregister COM objects, for both .DLL and .EXE files.
- File.exe -RegServer // for executable files
- REGSVR32 File.dll // for dll files

I use CreateProcess to launch the com registration and GetExitCodeProcess to get the exit code when completed.
But what do these return codes mean? Where can I find a Code<->Text translation?

For example, when I unregister with -UnRegServer I usually get a return code of 28, with REGSVR32 I usually get 53...
What do these numbers mean?

Any helps, clues, or hints would be immensely appreciated.
Thanks,

I found this.

http://support.microsoft.com/kb/249873