Regex problem II

Hi All ! I need to do preg_match("s/^\+//", $token), but when I did it, I received the message "Delimiter must not be alphanumeric or backslash in /www/new/index1.php on line 97" and manual say "Any character can be used for delimiter as long as it's not alphanumeric or backslash (\). If the delimiter character has to be used in the expression itself, it needs to be escaped by backslash". But I said: how can I escape the invalid char with backslash if the delimiter can't be backslash ??? It's crazy !!! :) Any idea.... Javier Leyba Buenos Aires, Argentina