>> Fiscal Period can be 1 to 13 or “0” in the import file. If it is 0, the period will be determined based on the Fiscal Date.

I went back to my notes and found this reference as well but also found that I was unable to make it work - a value always had to be there.

Upon further digging the other vendor confirmed that he did not change the software but did error on one of the translation forms used which led to the value of 0 in the exported file.

Once the other vendor fixed that problem we were once again able to import.

At the end of the day I'd like to thank everyone for the feedback and ponder why importing is not possible with a value of 0 in the fiscal period even though it is no longer an issue!

Cheers, JK