Exec() not working from web, but does from command line

I have a simple php script and all it does is call an "exec" function for a process on the server, that won't seem to work when I run it through the Web.

In all other cases, running the command line itself or even using php at the command line to run the .php script, it runs fine. I've checked to make sure that php.ini is not in safe mode though that shouldn't matter.

I'm really at a loss right now, and I'm a web designer more than a server tech, so any thoughts would be appreciated.

Sorry, obvious ownership issue. Wasn't logged in as www when testing. Apparently I could use some sleep...if only the bosses thought that was appropriate.