Visual Basic 6 Program Quits without any runtime error

Dear Experts,

i have a weird Problem going on since i last compiled a program of mine..
on many computers... if an error occurs, i no longer get runtime errors.. the executable simply gets killed... and disappears..  (it doesn't remain in memory)

if i repeat the same steps to reproduce the error in the visual basic 6 ide, then i get the runtime error, and i'm able to fix it..

however, sometimes my clients call me and say that the program disappears.. and actually they don't know what to say, because they don't have neither a screenshot of the error, nor the error msg.. so it's hard for me to debug the version..

any hints?

p.s. it's happening often, with many clients.. and on different machines.. so it's not a certain machine or operating system issue...

i've seen it.. on windows xp sp3, windows xp sp2, and windows 2003 server sp1

i appreciate your help,

cheers,