Anyone help with this '

[Dave]

Go to your plugins in the admincp and look for the register_start hook of that plugin.

Find:

$emailalreadyused = $db->query_read("SELECT * FROM " . TABLE_PREFIX . "userregcode WHERE userregemail = '$email'");

Replace with:

$emailalreadyused = $db->query_read("SELECT * FROM " . TABLE_PREFIX . "userregcode WHERE userregemail = '" . $db->escape_string($email) . "'");