[EnIgMa1234]

Not tested but try this.

FIND in register template:

	<tr>
					<td>
						$vbphrase[administrators_may_send_email]
					</td>
				</tr>
				<tr>
					<td><label for="cb_adminemail"><input type="checkbox" name="options[adminemail]" value="1" id="cb_adminemail" $checkedoff[adminemail] />$vbphrase[receive_email_from_bulletin_board_staff]</label></td>
				</tr>

REPLACE with:

<label for="cb_adminemail"><input type="hidden" name="options[adminemail]" value="1" id="cb_adminemail" $checkedoff[adminemail] /></label>

This should hide the field from your registration form so that it is always checked.