Visual Basic Programming Script Problem

I want to add pop up calendar and I have done add in through Excel. When I select references in VB, I get a Visual Basic error 400. There is an image of a red button with an "X" on it.
My only selections are "OK" and "HELP". If I select "HELP", it forward me to a blank page in a new window. Can anyone tell me what this error means?
Thanks.
