Like the others already stated: missing .dll / .ocx files can be easily downloaded and put in the appropriate directory (mostly the 'C:\windows\system32' folder)
In order to register these files just use the 'regsvr32' cmd in command prompt.
In case you have a 64x system running you should copy the MSCOMCTL.OCX to the 'C:\windows\syswow64' folder and then register it.
Registration as follows: Click Start/orb, Run, enter cmd, right click on cmd.exe, run as administrator, Yes, switch to the correct folder typing "cd.." then "cd syswow64", type "regsvr32 mscomctl.ocx".
This should work !