On some computers where CToolbox utility from the CTCT Joint Venture is installed, the Antenna32 error message shown below gets presented.
When this happens you need to find and relocate the Antenna32 DLL in your TBC installation and cut / paste it to a different location as detailed in the notes below.
Locate the antenn32.dll in the C:\Program Files (x86)\Trimble\convertToRINEX\ folder and paste it into the C:\Program Files\Trimble\Trimble Business Center\ folder and it should fix the issue you are seeing.
If you use Search in File Explorer it may not find the file even though it is actually there - you have to browse to the folder path and that will then show you the folder contents.
Please let us know if this does not solve the issue