I need help in
Too
Is iterating through the registry a possibility? I know that that doesn't give you a snapshot of what your instance of Excel is using, but what a new instance would use - but depending on what you need it for, it might be good enough.
The relevant keys are:
'Active add-ins are in values called OPEN*
HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Excel\Options
'Inactive add-ins are in values of their full path
HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Excel\Add-in Manager