executing a external command.....

[PLAnt]

Hello ppl,
I'm with a seious problem here.......🙁

I'm trying to execute a external command 'file.exe' that generate a file (image) from a scanner and the problem is when I execute the file in a DOS window I can hear the scanner working and generating the file but when I call the same command from php like exec("command") I can hear the same sound from the scanner BUT it doens't generate the file! 🙁(((

Is that a permissions problem?
I don't know what it is.....

Thanks in advance