Apps quitting unexpectedly

Okay so I'm on jaguar and every time (it seems) that I download a new app (in this case Skype)......it's just "quitting unexpectedly"....this is happening whenever there is a new mac update as well....any ideas?? I know I need some more RAM on this machine cause it's only 256 but this wouldn't be what's causing it would it?? :biohazard

Try repairing permissions. Though last time I had that problem it was dodgy RAM...