problem executing exe from php

[Andoni]

Hello all:

I have programmed an aplication to list all the tts voices of the
system in a txt file. When i execute it from the command line, it works
well . But if i do it by means of php accesing through web it executes
properly but the returned value of an COM interface function inside the
code is NULL, showing that there aren't any ttsvoices. It's as if i
hadn't access to the COM interface.

Any ideas?

Thanks in advanced.