New 2 ASP.NET --> not running in UserInteract

[Zabbah]

I'm trying a simple hello world:<BR>Private Sub Button1_Click(ByVal sender as...<BR> msgbox("hello world")<BR>end sub<BR><BR>When I click the button, I get:<BR>'It is invalid to show a modal dialog or form when the application is not running in UserInterActive Mode. Specify the ServiceNotification or DefualtDesktopOnly style to display a notice from a service application'<BR><BR>I read ASPFAQs on .Net, nothing there. I tried RTFM ('fine') but couldn't make heads or tails of it. What do I have to do to make this very simple example work?<BR>Thanks - old hand @ ASP, new to .Net<BR>...