java - Extended Data Table and DataScroller

Question

<rich:extendedDataTable sortMode="single" width="700px" value="#{gpsReport.reportSummary}"
                                                enableContextMenu="true" var="gps"
                                                selectionMode="single"
                                                rowClasses="tableRow1, tableRow2"
                                                id="tbl_gps" height="301px" rows="#{gpsReport.rowCount}" rowKeyVar="row">

                            <rich:column label="User" style="text-align: center" width="100px" >

                                <f:facet name="header">
                                    <h:outputText value="User" />
                                </f:facet>
                                <h:outputText value="#{gps.currentUser}" />

                            </rich:column>

                            <rich:column label="Time Stamp" style="text-align: center" width="140px" >

                                <f:facet name="header">
                                    <h:outputText value="Time Stamp" />
                                </f:facet>
                                <h:outputText value="#{gps.modifiedDate}" />

                            </rich:column>

                            <rich:column label="Latitude" style="text-align: center" width="110px" >

                                <f:facet name="header">
                                    <h:outputText value="Latitude" />
                                </f:facet>
                                <h:outputText value="#{gps.latitude}" />

                            </rich:column>

                            <rich:column label="Longitude" style="text-align: center" width="110px" >

                                <f:facet name="header">
                                    <h:outputText value="Longitude" />
                                </f:facet>
                                <h:outputText value="#{gps.longitude}" />

                            </rich:column>

                            <rich:column label="Location" style="text-align: center" width="240px" >

                                <f:facet name="header">
                                    <h:outputText value="Location" />
                                </f:facet>
                                <h:outputText value="#{gps.location}" />

                            </rich:column>

                        </rich:extendedDataTable>

                        <rich:datascroller align="center" for="tbl_gps"  />

Why does this code doesn't work? Am I missing something? This is the very same implementation I've used on the other page, it works actually. But no luck this time.