If you've tried everything that's been said and it doesn't work, this should be the be all end all for mscomctl.ocx errors.
In the .zip file for WinMip, you will see mscomctl.ocx. Copy that file and paste it in your SysWOW64 folder. You can find it by going to your C drive and clicking on Windows.
Open the command prompt as an administrator and type these commands exactly as they appear.
cd\
cd windows\
cd SysWOW64\
regsvr32 mscomctl.ocx
In the .zip file for WinMip, you will see mscomctl.ocx. Copy that file and paste it in your SysWOW64 folder. You can find it by going to your C drive and clicking on Windows.
Open the command prompt as an administrator and type these commands exactly as they appear.
cd\
cd windows\
cd SysWOW64\
regsvr32 mscomctl.ocx