MS Outlook vba code crashing Outlook

I have an Outlook vba macro which is crashing MSOutlook 2000 on some systems. When it crashes it produces a Dr Watson error.

I have isolated the problem to a subroutine called whenever the newInspector event is raised. It simply adds a new button on the toolbar.

This works fine on systems with MS Outlook 2000 and MS Office 2000 installed but crashes after opening several inspectors on systems with MSOutlook 2000 and MSOffice 97 installed. I cannot see any differences in the dependencies between the 2 systems and all references are made by my code have the relevant .dll resedent on both systems.

Does anyone have any idea what may be going wrong?
:(