Server error running snapshot

Hi,

I know this probably isn't a snapshot problem. I'm trying to run a snapshot which will backup all of my files (not the db), the site is quite large with loads of photo uploads.

I'm getting this error:

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Apache Server at trendjournal.mudpie.co.uk Port 80

I guess it is timing out. Do I just change a setting php.ini and if so which one?

Many thanks for your help,
Nichola