I suppose you meant "running a gauntlet" instead of just "a gauntlet"...
In German: Spießrutenlauf
Thanks for your time everyone, I've tested it will the standalone converter and same issue. Will now approach support as suggested. Will leave this unsolved and come back with the resolution once resolved.
Ok so the big reveal....... the issue was caused by an old file. So it turns out that the file(s) we are trying to convert are really old, created in 2001. Not sure why it produced that error but that's what it did.
We opened the file in Mathcad 15, re-saved and then was able to convert.
Once again, thanks all for everyone's input to begin with.