[Simon]

Macs don't crash unless there's something really wrong. Doesn't have to be something really bad, but definitely something wrong to make a Mac crash.

Did you keep repairing all permissions until Disk Utility could no longer find any permissions needing repair? I always make sure to run the (improved) Disk Utility after any application installation or upgrades to apps or system software, and I always run it again (as many times as needed) until Disk Utility can't find anything left to repair.

If everything was working fine before you upgraded your browsers and your system software, then I'd think the problem is more likely to be on your Mac than on the server. Cleo has a good point about trying to access that server from another computer to see if the problem(s) happen with that computer too.

I think you only have the one computer there, but someone you know could try it for you. Also, do you have the same trouble with PHP files on other servers? That would also indicate the problem is local, and not on your server.