My iMovie will not finalize!! Help!

I have tried to share my iMovie with the following, iDVD, i've tried to Export the Movie & Export using Quicktime. Neither work. They all say Error -108. I know this means something about not enough space on my computer so I tried to do all the previous but saving it to my External Hard Drive and it still will not work. I even Optimized my video to Large 960x540. I tried to clean up my Rejected Clips and it still wont work! I have to finalize this in 4 days before my brother's Wedding. Please help!!!!