Hvad betyder denne fejl?

Hej

Jeg får følgende fejl, når jeg vil oprette min bruger på min side:

Server Error in '/' Application.
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Showing a modal dialog box or form when the application is not running in UserInteractive mode is not a valid operation. Specify the ServiceNotification or DefaultDesktopOnly style to display a notification from a service application.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: Showing a modal dialog box or form when the application is not running in UserInteractive mode is not a valid operation. Specify the ServiceNotification or DefaultDesktopOnly style to display a notification from a service application.

Source Error:


Line 28:        Dim strError As Integer = 0
Line 29:
Line 30:        MsgBox(DDDay.SelectedValue & "-" & DDMonth.SelectedValue & "-" & DDYear.SelectedValue)
Line 31:
Line 32:        TxtPwd.Text = ViewState("Password")


Source File: W:\jtpdevelopmentdk\projekt\User\Create.aspx.vb    Line: 30

Men hvad betyder det helt præsis?