RE: When we had a custom report created to report on the active jobs, some of the jobs showed the job site location as typed into the job set up while others showed the letters na.

What sort of custom report? Is is running within QuickBooks like other reports?  Is it a transaction-based report including accounting data, or a list-based report just listing the jobs, similar to a customer contact report?

What is the column title that is is showing "na" as a value (I've never seen that in QB before)?

Can you send a screenshot? Perhaps that will clarify things.