Have you removed and re-added the report?

Yes, a Sage rep accessed by computer and re-created the report and still the same errors are coming up.

Is it a custom report or a standard? If standard which one? If custom and you want to send me a copy I can try it.

I'm not exactly sure what you mean by "a slip based invoice listing," but since you have tagged your post with both Customization and Custom Fields, I'm going to guess that you are using those elements in your report. Which could be adding to the complexity of the report you are trying to convert.

I would agree with Caren, it would help to "see" the old version, but as a general rule it should be doable.

Did support try to rebuild it from scratch with you?

Can you provide some insight into the purpose of attaching such a report to the invoice? What is the ultimate goal of having such a report? Perhaps there is an alternative report or method.