I was just trying to burn the Fedora 11 Preview DVD in XUbuntu and the default burning application logically uses /tmp as the location for temporary image files.

However my /tmp only had about 2.9 GB free space

The DVD is 3.8G and so the DVD burn failed due to lack of space.

So your options are:

Try to make /tmp bigger than a standard DVD (4.7+GB).

or

Set the temp location in your DVD burning utility to a nice fat volume.

I don't necessarily like to have acres of fallow hard disk space just waiting for one off use so I'm a fan of the second approach.