If you are having this problem with Glitchy's Model Editing Suite where you are missing the file 'mscomctl.ocx', then I found a fix right here.
http://www.majorgeeks.com/files/mscomctl.zip
Just extract it to your 'c:\windows\system\' folder,(for winxp it is 'system32\')
then
click start--> run and type
'REGSVR32 MSCOMCTL.OCX'
works after that