Nero 6 dilemma!

I am having a problem where if I compile a
number of MP3 files on a cd,I’ll save the compilation,go back to it ,later on and the
files that were just complied earlier are now ‘greyed out’,and worse still ,when I try to burn them,it’s asking for ‘the previous disc’,which is strange,because all the files in the compilation are still on my hard drive,and have not been altered or moved in anyway. All replies are appreciated…Thanks:cool:

Update: I’m not sure,but this may have something to do with my problem.:Cannot find the file 'C:\Winnt\system32\cmd32.exe,or one of it’s components