Error when print preview ' is not a valid integer.

SUGGESTED

Every time we print preview in QE->Reports->Invoice Details Report-> Selected preferred PDF-> Sort by Invoice# ->Reporting period, selected -February, then we received errors saying " ' is not a valid integer value".

If we keep on moving next page, the error persists - ' is not a valid integer. 

I'm not so sure where to look, because I cannot find the Transaction entry where I think we can somehow change the character there.

Has someone else encountered this kind of issue?

Any help/discussion/fix would be much appreciated.