.TXT file is empty

Hello Fellows,
I hope some one of you could help me. the things is that I recently implement on the CU site a kind of print using a .TXT file. So suddenly the CU told me that he has a problem with this king of printing. The problem is that the .TXT file generated is empty. He thought that the problem could be caused because of no data, but it does not the problem. He write a program that write a test messages and the messages was not stored into the .TXT file although the file was created.
I asked him to check the NATPARM so while He make the check I would like to know what can I check additionally.
The NATPARM definitions is:
LPT1 AUTO 80 132 32767 $SAG/Procesos/imprime01 D
LPT1 AUTO 80 132 32767 $SAG/Procesos/imprime02 D

Best Regards

Did you try to change the parameters from ā€˜Dā€™ (physical device) to ā€˜Fā€™ (file) ?