HtmlUnit test passes using 1.11, but not with 1.12 or 1.13

I'm using Canoo WebTest on top of HtmlUnit. The following test passes when I have HtmlUnit 1.11 in my classpath, but not when I have 1.12 or 1.13 in my classpath. Any ideas what changed?

    <target name="list">
        <webtest name="userTests">
            <config host="demo.appfuse.org" port="80" protocol="http" basepath=""
                resultpath="target/data" resultfile="web-tests-result.xml"
                summary="true" saveresponse="true"/>
            <steps>
                <invoke url="/appfuse-jsf/users.html"/>
                <setinputfield description="set user name" name="j_username" value="admin"/>
                <setinputfield description="set password" name="j_password" value="admin"/>
                <clickbutton label="Login" description="Click the submit button"/>
                <verifytitle text="User List | AppFuse"/>
                <clicklink xpath="//table[@id='editUser:users']/tbody/tr[1]/td[1]/a"/>
                <verifytitle text="User Settings | AppFuse"/>
            </steps>
        </webtest>
    </target>

Thanks,

Matt