Newbie question: where to find PHP errors?

[HerbCSO]

OK, I'll admit it, I'm having a total newbie issue here... I'm used to running PHP on servers I have full control over, so I'm not sure how to set things up here in this environment so I can see PHP errors. Been looking through the knowledge base, searched the forums already, tried setting a php.ini file, nothing doing so far. If somebody could point me in the right direction of where to read up on this, it would be much appreciated. I'm sure it must have been covered already, my feeble search skills are just not up to the task apparently, sorry! ;]

As for the specifics of the issue: I've configured the server to default to PHP5 through CPanel and I'm running a Joomla 1.5.9 install (deployed through Fantastico into a subdirectory of the main site). I tried changing some of the settings in the Global Configuration (wanted to have Search Engine Friendly URLs set to "Yes"), but every time I click "Apply", I get dumped back out to the main website. I'm guessing that some kind of PHP error is occurring, but have no idea what since I can't find the error message... ;]

HerbCSO