Sorry, I know nothing about Timberline or your specific problem. However the number of records returned does seem odd and sort of suggests checking if that number is always consistent or can be variable.
Does everything work OK if fewer records are retrieved?
If you retrieve fewer fields from the database does the record count increase before the failure occurs?
How are you connecting to the Timberline database?
There may be other information that could suggest ideas for approaches to the problem but this is all I can think of to ask to start with.