Most likely the probelm is on this line:
Dim intDistrict As Int32 = DirectCast(frmV.DataItem, DataRowView)("intContactPerson1DistrictID")
Before setting the value of the variable, check that it doesn't contain a null from database, which would be a DbNull.Value in .Net. For an example, see:
http://msdn.microsoft.com/en-us/library/system.dbnull.aspx[
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