Is it a custom applet? What does the applet do and how is it integrated with the GroupWise client (toolbars, events etc.)?
From experience and although rare, we’ve seen that it is possible for an applet’s operation to be sensitive to the state of a GroupWise user’s account. This can vary according to how the applet uses the GroupWise APIs and events and to the GroupWise Client version. A thorough GWCheck of a user’s account may help.
For at least on of the workstations with the problem, it is recommended that you upgrade to GroupWise 6.5.4 or later (6.5.6 is the latest).