The new ASPI has been reported not to work with all applications, and Adaptec/Roxio releases are buggy. If you are using Nero, I would use theirs (ASPI) since you know it is compatible. If I were you, I would try uninstalling ASPI layer. If there is no uninstall, try doing a search for wnaspi32.dll and delete the one in windows\system32 directory. Also don't install any other burning software like Easy CD, etc. since many don't get along well. Nero and MJ seem to work fine together on my machine, but I have no Roxio/Adaptec products which are well known for causing problems with other CD burning apps. Also, try disabing the XP built in crap, by going to MY Computer, right click on the CD burner drive, click properties, Recording tab, and disable the recording function. You can also go to Control Panel, Administrative Tools, Services, then Disable IMAPI CD- Burning COM Service. This will help Nero and other apps so they don't need to compete with the built in Roxio stuff that was included with XP.
Good Luck.