Why wont my movie burn ?

Ive been working on a birthday video using WMM for my dad since late March. It is only 35 minutes long with all the pictures and video clippings of his party. Ive been working on this video day & night for close to 3 months now. The burn keeps failing at 1.8% "unspecified error" while encoding. Ive taking the movie apart in attempts to burn.. some where good burns. But when I attached the complete movie/video together again... it Fails (1.8%) I have over 50 something files (changing names of movie while in efforts to fix the original) I initially thought the problem was the music track (stevie wonder-happy birthday) because ive turned a 5 minute song into a 15 min song by slicing and then copy-paste). all the music is in mp3 and all my movie clips ive converted to wmv, most of the still pix are ither jpeg, gif or/and 1 .pnp. I am using Windows Vista Home Premium, any advice or suggestions would be greatly appreciated. Please Help~