This is a very well-known Ubuntu problem. There's a long thread at the Ubuntu forum where people have compared their hardware to try and find what causes it, with no luck. The bug-tracking service says it's been fixed, but the latest version still has the problem on my desktop. This is the first time I've heard of it in Mint, though.
If you must have Ubuntu, get the alternative installation disk. The installer on that is not Ubiquity, so it will work, although it has no option for encryption. You might like to try Arios. That's an Ubuntu re-spin with Gnome 3 and a working version of Ubiquity. If you want encryption, make sure you have /home on its own partition, or that will lock up Arios's Ubiquity! See my review:
Pinguy is very similar to Arios.