How do I trap errors when excel (not a workbook) launches
 

I have developed a macro that makes use of the Calendar control however not
all computers within the organisation I work for have this component
installed and when you launch my applet on one of these machines you get the
two error messages "Microsoft Forms - could not load object" which have to be
acknowledged before the auto open event for the workbook starts and then
produces further error messages.

What I would like to do is include a check in my macro so that if the
calendar component is missing an error message is displayed telling the user
that the workbook cannot be used on this particular machine and then shut
down the Excel application.

Any advise would be greatly appreciated.

Many thanks

Richard