From MacFixIt, may help;
Persistent crashes: Delete .plist files, turn off plug-ins If you are experiencing repeated crashes from iTunes 7.0 -- especially when simply switching tracks -- there are two workarounds that could prove useful.
First, delete the following files:
com.apple.iTunesHelper.plist
com.apple.iTunes.plist
com.apple.iTunes.eq.plist
from ~/Library/Preferences, then quit and re-launch iTunes. Note that after deleting these files you will need to re-establish some iTunes preferences.
Failing the above, look in the following directory:
~/Library/iTunes/iTunes Plug-ins
and remove any third-party plug-ins (including visualizers) you have previously added, then quit and re-launch iTunes.
Hold option at launch to select different libraries/create new ones iTunes 7.0 has limited support for multiple libraries. You can choose a different library for the application by holding down the option key while it is launching. You can also create a new library at the time of launch via this method.