Outlook Add-In, cannot show form after click on toolbar button

[VKoen]

Private Sub _cbb_Click1(ByVal Ctrl As Microsoft.Office.Core.CommandBarButton, ByRef CancelDefault As Boolean) _
Handles _cbb.Click

Dim form As New frmMyCExport()
form.Show()
End Sub

I created an Outlook Add-In which adds a toolbar with one button in an Outlook Inspector. So far so good.

When the form is loaded following exception is trown :
"Could not load file or assembly 'Datalogic, version....'. Failed to grant permission to execute.

frmMyCExport makes uses of that assembly. How do I grant permission to that assembly?

I use:
-Windows XP SP2
-Outlook 2003
-.Net-Framework 2.0
-VSTO Runtime
-Outlook PIA

The Add-In is developed in Visual Studio 2005