XSD Erreur de Validation : cos-tous-limitée.1.2: Un modèle de groupe doit apparaître dans une particule avec

J'ai et XSD qui donne l'erreur suivante lors de la génération de schéma.

    org.xml.sax.SAXParseException; systemId: file:/D:/Basil/Projects/myproducts.xsd; lineNumber: 577; columnNumber: 50; cos-all-limited.1.2: An 'all' model group must appear in a particle with '{'min occurs'}' = '{'max occurs'}' = 1, and that particle must be part of a pair which constitutes the '{'content type'}' of a complex type definition.
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:198)
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:134)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:437)
    at com.sun.org.apache.xerces.internal.impl.xs.traversers.XSDHandler.reportSchemaErr(XSDHandler.java:4124)
    at com.sun.org.apache.xerces.internal.impl.xs.traversers.XSDHandler.reportSchemaError(XSDHandler.java:4107)
    at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaLoader.loadSchema(XMLSchemaLoader.java:588)
    at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaLoader.loadGrammar(XMLSchemaLoader.java:555)
    at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaLoader.loadGrammar(XMLSchemaLoader.java:521)
    at com.sun.org.apache.xerces.internal.jaxp.validation.XMLSchemaFactory.newSchema(XMLSchemaFactory.java:240)
    at com.sun.tools.xjc.reader.xmlschema.parser.SchemaConstraintChecker.check(SchemaConstraintChecker.java:101)
    at com.sun.tools.xjc.ModelLoader.loadXMLSchema(ModelLoader.java:357)
    at com.sun.tools.xjc.ModelLoader.load(ModelLoader.java:167)
    at com.sun.tools.xjc.ModelLoader.load(ModelLoader.java:113)
    at com.sun.tools.xjc.Driver.run(Driver.java:313)
    at org.codehaus.mojo.jaxb2.AbstractXjcMojo.execute(AbstractXjcMojo.java:298)
    at org.apache.maven.plugin.DefaultPluginManager.executeMojo(DefaultPluginManager.java:490)

Pertinentes XSD est collé ci-dessous. Je ne suis pas en mesure de comprendre quelle est l'erreur réelle. L'erreur est sur la troisième ligne de fin. S'il vous plaît aider.

<xs:group name="prodVar">
<xs:all>
<xs:element name="prodVar" minOccurs="0" maxOccurs="1">
<xs:complexType>
<xs:sequence>
<xs:element name="varName" type="xs:string" minOccurs="0" maxOccurs="unbounded" />
<xs:element ref="skuList" />
<xs:element name="vStory" type="xs:string" minOccurs="0" />
<xs:element ref="attList" />
</xs:sequence>
</xs:complexType>
</xs:element>
<xs:element name="colorSwatchList" minOccurs="0" maxOccurs="1">
<xs:complexType>
<xs:sequence minOccurs="1" maxOccurs="unbounded">
<xs:element name="colorSwatch" minOccurs="0" maxOccurs="unbounded">
<xs:complexType>
<xs:sequence>
<xs:element name="swatchName" type="xs:string" minOccurs="0" />
<xs:element name="swatchHeight" type="xs:string" minOccurs="0" />
<xs:element name="swatchWidth" type="xs:string" minOccurs="0" />
<xs:element name="colorName" type="xs:string" minOccurs="0" />
<xs:element name="mainImageHeight" type="xs:string" minOccurs="0" />
<xs:element name="mainImageWidth" type="xs:string" minOccurs="0" />
<xs:element name="mainImageName" type="xs:string" minOccurs="0" />
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:sequence>
</xs:complexType>
</xs:element>
</xs:all>
</xs:group>
<!--lot of other stuff -->
<xs:element name="prodVarList" minOccurs="0" maxOccurs="1">
<xs:complexType> <!-- ERROR HERE -->
<xs:group ref="prodVar" minOccurs="0" maxOccurs="unbounded" />
</xs:complexType>
</xs:element>