Call custom Transaction and get back

Hi,

I have some issue to use call transaction 'YXXX'. If I process on a display 'A' mode I find out that is execute successfull, but did not go back to my code until I use green arrow and force to get back. If I process on no-display mode it comes back with SY-SUBRC = 1001. If any idea why it is doing like that and how to fix it?

Thanks a lot,

Vera