FILE*'s are constructed by the C runtime library, which may necessitate you dragging in a whole lot of stuff you didn't want. If you did want it, there would seem to be little point in writing this bit in ASM.
Dim Adapter As New OleDbDataAdapter
Dim Command As New OleDbCommand
Dim xFrom As String = dtpFrom.Value.ToString.Substring(0, dtpFrom.Value.ToString.IndexOf(" "))
Dim xTo As String = dtpTo.Value.ToString.Substring(0, dtpTo.Value.ToString.IndexOf(" "))
sqlQuery = MainQuery ...