Maybe you can follow on this topic regarding overburning.
http://www.cdrinfo.com/forum/topic.asp?TOPIC_ID=8119 quote:
bur nero keep saying that I don't have much space on the cd... & that I need to put bigger cd... (even that the cd have the needed space)
Nero will not detect the LARGE capacity CDRs (90min/99min) CDR as 90min/99min respectively. Nero will only show a maximum of 80min no matter what CDR u put in, despite the size is 100min or whatsoever. I read from other forum saying that official maximum CDR size is 80min/700MB, hence the limitation on the burning software.
Dont bother about the prompting about insufficient disk space. As long as you've enable & set the overburning capacity to be higher than your compilation, you will able to burn them. Somehow, Nero will prompt you for confirmation before overburning the CDR. Click it anyway.
As for the fail of burning, have you tried reading the disk? There are quite a number of reason for the overburning failures.
1) Drive doesnt support overburning. I dont believe this is your problem. Anyway, u can check this in Nero. Click on "Chooses a recorder" and you can see the drive's features.
2) Drive is too old or condition is not good for overburning due to wear and tear. Yes, I've got an old Acer drive here, 8x4x24x, unable to overburn my 80min CDR as much as my new LiteOn drive can do. Hence the drive problem.
3) I've heard of this problem with some drives, that you will get fail burn when doing Disc-At-Once burn. My friend always complained about this when using his Creative drive. Somehow, I manage to use it without problem. So I m not sure whether your drive is in this category.
Last, try to run an overburning test using Nero CD Speed, set the speed to 8x or 16x. See what's the maximum capacity your drive can go. :)
Good Luck!
Note: CD Speed not 100% accurate, as my 80min CDR finished the test at 48x 99min 57sec without problem.