ActiveWorkbook reference fails
 

Here's my problem. I've made an add-in that is used as a base library for a
number of Excel reports. It all works fine when I run Excel in the usual
way. But I can also start my Excel reports from my private web application.
In that case, Excel is started in internet explorer, the add-in is loaded
and my report is opened. But when the add-in uses the ActiveWorkbook-keyword
to reference the workbook opened in the browser, everything goes wrong. I
don't understand the problem, because this works fine if the report runs in
Excel in a normal way. Is this caused by the fact that the Excel workbook
isn't the active workbook, because it runs in the web browser instead of in
Excel directly? How can I fix this? Can anyone help me?

Thx,

Lieven