Interop_translator.exe - Unable to Locate Component - JSOGROUP.dll
This is caused because there is likely a dependency on a Catia V5 library present. The Step file itself contains references to Catia V5 files. The parts it is referring to are CATPart. Therefore, it needs the Catia libraries and these CATParts to translate.
1. Go back to the Catia V5 system and export a file without dependencies on other files. This should be a translator that can be imported in GAMBIT. You may want to try exporting to some other format besides Step. This may be sufficient.
2. Collect all dependent Catia V5 files referenced by the existing Step file and try to use another system to import (for example, WorkBench or SolidWorks). Then try exporting to a format that GAMBIT can import.