Ypager crashes or performs an illegal operation on startup or right click

This error often occurs because you are using a third party skinning application that modifies the Windows Look/Interface. You need to either remove the program, or open the settings, and disable the skinning of Yahoo! Messenger / YPager in the skinning application's settings.

Two known programs to cause this are Window Blinds and AlienGUIse. Window Blinds has a "per application" setting to override this.