How do I add a CommandbarButton to a new Inspector object

[Peter]

I am trying to add a CommandBarButton to the 'standard'
CommandBar whenever a new Inspector object is opened.

I have a sub fired when the NewInspector event is raised
and this includes the following line:

Set cbtn = cbars("Standard").Controls.Add(msoControlButton)

This line normally works OK except that on certain systems,
it intermittently crashes outlook with a Dr Watson error.
The frequency of crashing can be as low as once in every 4
new Inspectors. I have not been able to generate the
problem using the environment Outlook 2000 and Office 2000
but it does exhibit itself using Outlook 2000 and Office 97
environment. However, all dependencies and required .dll
files are correct and at the correct versions.

Does anyone have any suggestions on what could be causing
these crashes?

Peter