I tried to validate the an XSD, using on on-line xml validator (http://apps.gotdotnet.com/xmltools/x...r/Default.aspx)
but returned following error:
Validation error:

Cannot resolve schemaLocation attribute. An error occurred at , (3, 4).

The 'http://www.w3.org/2000/09/xmldsig#:Signature' element is not declared. An error occurred at , (69, 10).

The xsd is:

<?xml version="1.0" standalone="yes"?>
<xs:schema id="NewDataSet" targetNamespace="http://www.jjj.com/jjjCoupler" xmlns:mstns="http://www.jjj.com/jjjCoupler" xmlns="http://www.jjj.com/jjjCoupler" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata" attributeFormDefault="qualified" elementFormDefault="qualified" xmlns:app1="http://www.w3.org/2000/09/xmldsig#">
  <xs:import namespace="http://www.w3.org/2000/09/xmldsig#" schemaLocation="trywritetxt1_app1.xsd" />
  <xs:element name="jjjCoupler">
    <xs:complexType>
      <xs:sequence>
        <xs:element name="jjjSession" minOccurs="0" maxOccurs="unbounded">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="PatInfo" minOccurs="0" maxOccurs="unbounded">
                <xs:complexType>
                  <xs:attribute name="FName" form="unqualified" type="xs:string" />
                  <xs:attribute name="LName" form="unqualified" type="xs:string" />
                  <xs:attribute name="MName" form="unqualified" type="xs:string" />
                  <xs:attribute name="id" form="unqualified" type="xs:string" />
                </xs:complexType>
              </xs:element>
              <xs:element name="SessInfo" minOccurs="0" maxOccurs="unbounded">
                <xs:complexType>
                  <xs:sequence>
                    <xs:element name="Cmt" type="xs:string" minOccurs="0" msdata:Ordinal="1" />
                    <xs:element name="CplInfo" minOccurs="0" maxOccurs="unbounded">
                      <xs:complexType>
                        <xs:attribute name="CplNo" form="unqualified" type="xs:string" />
                        <xs:attribute name="Name" form="unqualified" type="xs:string" />
                        <xs:attribute name="Rev" form="unqualified" type="xs:string" />
                      </xs:complexType>
                    </xs:element>
                    <xs:element name="FndInfo" minOccurs="0" maxOccurs="unbounded">
                      <xs:complexType>
                        <xs:sequence>
                          <xs:element name="FndTxt" type="xs:string" minOccurs="0" msdata:Ordinal="0" />
                          <xs:element name="FndValue" minOccurs="0" maxOccurs="unbounded">
                            <xs:complexType>
                              <xs:attribute name="FValType" form="unqualified" type="xs:string" />
                              <xs:attribute name="FValValue" form="unqualified" type="xs:string" />
                              <xs:attribute name="FValUnit" form="unqualified" type="xs:string" />
                            </xs:complexType>
                          </xs:element>
                        </xs:sequence>
                        <xs:attribute name="Chksum" form="unqualified" type="xs:string" />
                        <xs:attribute name="CplNo" form="unqualified" type="xs:string" />
                        <xs:attribute name="EntNo" form="unqualified" type="xs:string" />
                        <xs:attribute name="RecNo" form="unqualified" type="xs:string" />
                      </xs:complexType>
                    </xs:element>
                  </xs:sequence>
                  <xs:attribute name="ProvID" form="unqualified" type="xs:string" />
                  <xs:attribute name="SessID" form="unqualified" type="xs:string" />
                  <xs:attribute name="SessTime" form="unqualified" type="xs:string" />
                </xs:complexType>
              </xs:element>
            </xs:sequence>
            <xs:attribute name="id" form="unqualified" type="xs:string" />
          </xs:complexType>
        </xs:element>
        <xs:element name="jjjEngine" minOccurs="0" maxOccurs="unbounded">
          <xs:complexType>
            <xs:sequence>
              <xs:element name="GenInfo" minOccurs="0" maxOccurs="unbounded">
                <xs:complexType>
                  <xs:attribute name="FirstView" form="unqualified" type="xs:string" />
                </xs:complexType>
              </xs:element>
            </xs:sequence>
            <xs:attribute name="id" form="unqualified" type="xs:string" />
          </xs:complexType>
        </xs:element>
        <xs:element ref="app1:Signature" />
      </xs:sequence>
      <xs:attribute name="Ver" form="unqualified" type="xs:string" />
    </xs:complexType>
  </xs:element>
  <xs:element name="NewDataSet" msdata:IsDataSet="true">
    <xs:complexType>
      <xs:choice maxOccurs="unbounded">
        <xs:element ref="jjjCoupler" />
      </xs:choice>
    </xs:complexType>
  </xs:element>
</xs:schema>



Any help would be greatly appreciated.