Snow Leopard fail install from disk

Hi I am hoping someone can shed some light on my problem.

I have an iMac late 08 model and recently after trying a fresh reinstall with Lion things went strangely wrong. I was getting beeps on start up so i took out a stick of ram and now it seems to start up as normal with the chime. Because I had erased the disk there is no OS to boot, so when I boot from my legit snow leopard disk that all works fine. When I try to install snow leopard it hangs and eventually says "could not copy the necessary files" when i check the install log there is a list of errors. I have now began to install the original OSX disks that came with my iMac as I type this with the error list open and I am not experiencing the same problems. It all seems to working fine fingers crossed. So i guess my problem may be with the snow leopard disk or there is a more fundamental issue somewhere.

Thanks.

Alex

Personally I never install from disc. Sounds like your superdrive has gotten a bit fussy in its old age. If you've already got a legit licensed copy of Snow Leopard I would try and install from USB:

Using a machine with a good drive then you could make an image on that.

Fail that maybe someone can tell us if it's legal to download an image being as you already have the license. Optical media belongs in the history books