Hello Guys I have a problem in Downloading After Click on Download # appears in url and UTF-8 warning appears I dont understand what has happened it was working previously

WARNING: PWC4011: Unable to set request character encoding to UTF-8 from context /mercweb, because request parameters have already been read, or ServletRequest.getReader() has already been called

<rich:column style="width:35%;" id="evntcol6">

                                                                    <f:facet name="header" >Attachment</f:facet>

                                                                    <rich:dataTable value="#{event.files}" var="file" id="table1"

                                                                                    style="width:100%;border: 0px;">

                                                                        <rich:column style="width:20%;  border: 0px;" id="eventdscol6">

                                                                            <h:outputText value="#{file.fileDescription}" id="eventdstxt6"/>

                                                                            <h:commandLink actionListener="#{eventMaster.downloadFile}"  value="#{lbl['label.download']}" id="eventdcmddownld">

                                                                                <f:param name="fileName" value="#{file.uploadedFileName}"/>

                                                                                <f:param name="caseFileId" value="#{file.caseFileId}"/>

                                                                            </h:commandLink>

                                                                        </rich:column>

                                                                    </rich:dataTable>

                                                                </rich:column>