I've tried installing freetime (I know how to install EP's , I have all the other EP's installed), and it gave an error message saying a file won't install properly or something of that sort. It's on the first disk, around the 43% complete mark. Can anyone help me? Thanks!

Try taking your disk to a video shop you frequent and asking them to clean it. Might not be the issue, but it can be sometimes.

It is definitely possible that there's a scratch or something on the disc that's causing the installation to fail. Could be a faulty disc too. I doubt the actual data on the disc is bad, so I would assume the problem is with the disc itself. There are probably programs out there that will check discs for problems, try a google search for cd error checking software.

Disc cleaning tips and manual install instructions here:
http://simswiki.info/wiki.php?title=Game_Help:Install