As you can see by the path the MSCOMCTL.OCX comes with the OS and hasn't got anything to do with MS Office - it only can be used by the Office program.
Just for you to know: There was a problem with the update of this file, so you might experience difficulties to install a newer version of the file. Therefore I suggested, to contact the external company first. The developer should know what's required to run his "program" and if MSCOMCTL.OCX is really the cause of the error.

... yes I would apreciate to know any solutions you find, or even if not ...

No luck updating that file

Going to contact the sender of the file, it's strange how only two people (so far) have the issue opening the file. While, myself and a colleague can open it completely fine!