These questions below may be for a different product... but the information you need to supply is the same, for the products you use
-Information FAQ http://forums.adobe.com/message/4200840
Starting with a very basic bit of information... Windows or Mac?
I wasn't sure how this system works!
As a test, instead of Burning to Disc, can you instead Burn to Folder?
If so, then you can use the created VIDEO_TS folder (with all the necessary IFO, BUP and VOB files inside), with the great, free burning utility, ImgBurn, to Burn to Disc. This will also allow you set it up to burn X numbers of copies, and basically all you have to do is insert blank media.
Good luck, and please let us know if Burn to Folder works for you. If not, please let us know how much defragmented free-space you have on both your C:\ drive, and also the drive, that you set for the destination with Burn to Folder.