Question mark in regex

I have the following rule, which I've just moved over from a 4.5 system to 9.1.1:

rule JTS_olgc-prod_http_10 {
   when HTTP_REQUEST {
        if {    [HTTP::host] == "xxx.com.au"
            and ( [matchclass [HTTP::uri] ends_with $::JTS_FileTyp]
                or [matchclass [HTTP::uri] equals $::JTS_AbsoluteURI]
                or [HTTP::uri] starts_with "/images/"
                or [HTTP::uri] matches_regex "^/default\.asp\?(action|menu|page|text_only)="
                or [HTTP::uri] matches_regex "^/(general|gaming|pdf|calendar.html).*"
                or [HTTP::uri] matches_regex "^/(splash|src/js)/.*\.js$" ) } {
        }
        else {
            log local2.notice "Denied: Source: [HTTP::header value X-Forwarded-For] Method: [HTTP::method] Host: [HTTP::host] URI: [HTTP::uri]"
           use pool jts-utility-pool
        }
    }
}

I am having problems with the line

or [HTTP::uri] matches_regex "^/default\.asp\?(action|menu|page|text_only)="

The expression will not match the question mark (?), whether I precede it with an escape \ or not. In the end I have replaced it with a dot (.).

An example of a URI which I thought should match, but doesn't, is

/default.asp?page=casino.casino.htm&menu=casino

Is there a special meaning for the question mark in v9?