C/C++ on NT

Hello friends
It is related to NT system calls problem. I am calling a 16-bit application( say X.exe) through CreateProcess() in my program. My program executes after loogon( before opens the desktop). It is on pentium with NT m/c. At first logon( i e at bootup the application(x.exe) is not running but createProcess is returning true. If I logoff and logon then the application(x.exe) is running. I don't get what is the difference btwn first logon and secound logon. Please assist me how can I getrid of this proble.
Thanks in advance,
Chiranjeevi.