FUNL0200 Getmain failure attempting to append to long string at line (n); Fast/Unload cancelled.

The most likely cause of this error is a very large number of %variables being assigned strings longer than 255, or a very large number of CHANGE, or especially, ADD, statements for BLOB or CLOB fields. While it is possible that increasing the region size available to Fast/Unload will correct the program, you should first examine your FUEL program logic.

The error occurred while executing line n of the FUEL program, although if there is an error in your logic, it may be at a different line which updates a %variable or BLOB or CLOB field.