the problem is that the recordset code is after the server validation code, the recordset code needs to be moved so it is before the server validation code.
also, the recordset is not being filtered, you should filter the email columnb on the email form element.
Instead of using like entry validation, use number validation. the idea is to check that the rcordset is empty.
for the server variable, use $totalRows_rsEmailMatch. In the number validation settings, set the minimum number to -1 and the max to 0