I've had this happen to me a few times as well. I find trashing the help's preference files usually solves it. They're in your ~/Library/Preferences/ folder, with the following names:
com.apple.help.plist
com.apple.helpviewer.plist
After they're gone, it should start working again...
Comments
com.apple.help.plist
com.apple.helpviewer.plist
After they're gone, it should start working again...
Neil.
a.k.a. Arnel
Thanks a lot. It seems that the bug is fixed.