I just dropped in the new RC4 instead of RC3 which worked fine other than the reverse ajax only notifying every 60 seconds (see http://getahead.org/bugs/browse/DWR-54). The new version does NOT solve the problem of reverse ajax only notifying every 60 seconds... for both FF2 and IE7.

In addition now IE7 throws JS errors whenever it renews the ReverseAjax connection - which is every 60 seconds or every time it tries to do the Polling Only.

Here is the web.xml config for reference:

    <servlet>
        <servlet-name>dwr-invoker</servlet-name>
        <servlet-class>org.directwebremoting.servlet.DwrServlet</servlet-class>
        <init-param>
            <param-name>debug</param-name>
            <param-value>false</param-value>
        </init-param>
        <init-param>
            <param-name>crossDomainSessionSecurity</param-name>
            <param-value>true</param-value>
        </init-param>
        <!-- default script timeout (milliseconds) -->
        <init-param>
            <param-name>scriptSessionTimeout</param-name>
            <param-value>1800000</param-value>
        </init-param>
        <!-- What is the maximum number of calls that can be done in a single batch -->
        <init-param>
            <param-name>maxCallCount</param-name>
            <param-value>20</param-value>
        </init-param>
        <!-- Set to true to enable polling and comet. This can increase the load on your server although DWR does have mechanisms to prevent server overload. -->
        <init-param>
            <param-name>activeReverseAjaxEnabled</param-name>
            <param-value>true</param-value>
        </init-param>
        <!-- include querystrings in reverse ajax page uniqueness -->
        <init-param>
            <param-name>normalizeIncludesQueryString</param-name>
            <param-value>true</param-value>
        </init-param>
        <!-- What is the maximium number of threads we keep waiting. We reduce the time within poll to reduce the load. -->
        <init-param>
            <param-name>maxWaitingThreads</param-name>
            <param-value>20</param-value>
        </init-param>
        <!-- What is the maximum number of hits we should get per second. We increase the poll time to compensate and reduce the load. -->
        <init-param>
            <param-name>maxPollHitsPerSecond</param-name>
            <param-value>40</param-value>
        </init-param>
        <!-- How long are we telling users to wait before they come back next (in milliseconds) -->
        <init-param>
            <param-name>timeToNextPoll</param-name>
            <param-value>5000</param-value>
        </init-param>
        <!-- The max time we wait before opening a stream to reply (in milliseconds) -->
        <init-param>
            <param-name>preStreamWaitTime</param-name>
            <param-value>29000</param-value>
        </init-param>
        <!-- The max time we wait after opening a stream before we reply (in milliseconds). -->
        <init-param>
            <param-name>postStreamWaitTime</param-name>
            <param-value>1000</param-value>
        </init-param>
        <load-on-startup>3</load-on-startup>
    </servlet>