message reads 'apple application support for itunes helper Error 2', followed by a note to uninstall Itunes and re-install.
With that one, actually the best thing to do is uninstall
both Apple Application Support and iTunes and then reinstall iTunes (which should reinstall your Apple Application Support).
The following set of instructions is worth trying.
http://discussions.apple.com/thread.jspa?messageID=11266971�
Under normal circumstances, an uninstall of iTunes doesn't touch your content files. That being said, it's still always prudent to have a backup. If your content and library files are in their default locations, taking a copy of the entire "itunes" folder (not just the "itunes media" folder) discussed in the following document is a good straightforward way of getting one under your circumstances:
[iTunes: Where to find the contents of your iTunes library|http://support.apple.com/kb/HT2279]
