Do check if you have removed both the important Roxio preference files prior to re-installing. Snow Leopard didn’t hide the ~/Library folder by default yet, so this should be fairly easy. (These two files will be re-created freshly on the next launch.)
~/Library/Preferences/Roxio Toast Prefs
There are other files if you want to be thorough in removing any trace, but they shouldn’t interfere with the launch of the main Toast app.
/Library/Application Support/Roxio/ ( ← not sure if either or both Application Support folder was used)
~/Library/Application Support/Roxio/ ( ← not sure if either or both Application Support folder was used)
~/Library/Saved Application State/com.roxio.Toast.savedState/ ( ← only 10.7 Lion and later)
There may be even more caches and temp files, but those shouldn’t be accessed at launch, especially after a reboot.
Do try to launch Toast without any peripherals attached (unplug anything non-Apple).
Did you install/update software with firmware, drivers, kernel extensions, codecs, or something similar that Toast may notice? New devices or PCI-cards present?
Can you create a new user and install Toast under that account? Will it launch then? If so, then the issue HAS TO BE specific to the old account (and not Mac OS X or the Roxio software), so you know where to look/narrow it down.
I won’t claim to be able to read a crash log, but I did notice “EXC_BAD_ACCESS (SIGBUS)”, which I’ll use as a lead.
(From the Apple Support Communities ) A SIGBUS exception is typically caused for one of two reasons — either the presence of a bug in the software in which it occurred, or the presence of faulty RAM. Have you tried running your Mac’s Apple Hardware Test, to see if it can detect any problems with its RAM? (Note that the AHT cannot detect all possible RAM defects, so even if it is unable to identify a problem, that isn’t a guarantee that no problem exists.)
RAM modules have no moving parts, so if they go bad, it is probably from an electrical charge. Do you know of a recent power surge? Has the Mac been open, could the RAM modules have been touched by someone with a static charge? Is your Mac very dusty inside? (If the issue is RAM, then I would expect that you would also notice crashes outside of Toast.)
Or suppose your ‘dyld shared cache’ was altered by anything else than an Apple installer or updater. Then a sudo update_dyld_shared_cache -force (+ reboot) may get things right again for this application to launch without crashing.