OOps - think I may you an apology. You didn't show the code where "user" was declared, and I probably guessed wrong, and thus gave bad advice.
If, as I now suspect, "user" is one of the Reader classes then it won't have a method to read ints directly. If that's the case, look at Integer.parseInt(String s).
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 ...