Nero giving me trouble

I burn my 3 year olds movies with nero 7, I use dvd shrink to copy to an external drive Buslink (K:). I open nero 7 import the movie from buslink it does it’s thing when i go to next srceen I have had a problem that started on wednesday, in the Destination: box it reads E:tsstcorpcddvdw the next box reads folder for temporary files, K:\VIDEO_TS, now when I go to burn it it sends it to a file in the buslink, and then trys to burn it to my DVD+R but fails to do so. It also sometimes tells me the disc in the drive is not writable, DVD+R is all i have ever used. Someone please tell what is the problem with this program I know very little about programs or computers