After about 2 months of test to discover why my cd or dvd burings always crash nero at the very end of the disc ( 99% most of the time ) I found that Nero 6.x is incompatible with Trillian 2.x, if I close trillian I have no problem, but if trillian is running while I burn a cd or dvd it will cause nero to crash at the end of the disc, not always but 1 on 3 times...
Probably it's a issue with my configuration because i tryed to install nero and trillian on other system and no problem :\
I've also tryed to burn cd with other cd-burner and the same thing happened.
So I'm posting this in order to help somebody who have similar problem, maybe caused by Trillian like me.

Nero (especially version 6.0 and above) is very sensitive to any kind of applications running in the background. One should exit all background applications, such as virus scanners, firewalls, caching utilities in order to ensure proper nero operation.

I still use Nero 5.5 and I have never had a problem with background applications, except other CD/DVD drive utility applications.

Neo The Matrix

I am using Nero 6 and Trillian Pro for a long time now and never observed the problems you have mentioned - i am not doubting your ability to troubleshoot i am merely saying that if this is the problem then it doesnt reproduce 100%.

Maybe some more info on your system (software/hardware) might help.

Hemispasm, I noticed the same thing but I can't explain why this is happening...an Instant messaging software should not interfere in any way with a buring software (but, you never know, we are under Micro$oft )
My system:

Windows XP SP1

P4 2400 Mhz
Asus P4C800
512Mb Pc3200 dual channel ram
Pioneer DVR-A107 (1.13 firmware)

Usually antivirus or firewall are know to cause some problem but I'm using Symantec Antivirus Server 8 & Norton Personal Firewall and I never had any problem (however I tryed to disable them and enable trillian but nothing changed, nero crashed)