Hi,
I've got the solution.
The problem wasn't at Java (unbelievable I know). It was a mistake at the abap site.
wrong:
CL_GUI_FRONTEND_SERVICES=>EXECUTE
document = 'some_executable.exe'
right:
CL_GUI_FRONTEND_SERVICES=>EXECUTE
application = 'some_executable.exe'
Then everything works just fine.
regards
Martin