Exception occurs each time event handler fires

[RVH]

Hello experts,

I'm currently extending some screens in C4C. This is going fine, but each time I add a new button to a screen and implement a corresponding event handler, I am greeted with the following message when I click the button:

This also happens when, for example, an event handler is fired due to an InPort value being read (using the RequestFireOnInitialization property).

The thing causing this is definitely the firing of an event handler.

Anyone who knows a solution?

[RVH]

Finally managed to solve this problem; My mistake was that I used the Foundation deployment unit for my solution instead of the Customer Relationship Management deployment unit.