There are lots of threads on this problem I had it too, so have a wander around the forum its fun !
Normally its as simple as using good quality discs, burning your disc as slow as possible then, checking the md5 sum on your burned disc.
Dunno why but I had to reset the settings in my bios to get mine to work (Prob coz I like messing about) but no-one else seems to have had to do this, so last resort thing ok.
Im sure our friendly moderators and Mint programmers will come up with a better solution for you so be patient, what will help them is if you still cant get it working, put up your computer specs, ie - laptop, desktop? proccessor and all that stuff !