Please move this to Products. The specified item was not found. is for generic marketing questions.
This is an SFDC issue in the first place. You very likely have some workflow in SFDC that do this and assign the PA record type to the new contacts when the company is empty, but that workflow does not test on non empty yet meaningless values such as "none" or "N/A".
You can change the SFDC workflow, but there will always be some values that will not work, so I would recommend that you look at it from the process standpoint and replace the SFDC standard conversion assistant with a custom one. You will need to talk you a SFDC partner for this.