I have a G4 desktop with a Superdrive and am trying to burn a DVD from a (mac the ripper) ripped VIDEO_TS folder. I have tried Memorex, TDK and Imation DVD's (some -R and some +R), however whenever I've tried I get a "waiting for the writer" message and it won't burn. Any ideas what the issue might be? Thanks for any help.

It could be any number of things. Instead of burning directly to disc, try making a disc image (its an option on the file menu). If it works making a disc image then Toast is working ok. From there try other media and firmware updates for the drive. If it fails when writing to the image file, post the exact error and any details back here again.