Schema Will not Validate Invalid Content Errors

I am trying to validate an XML schema but I keep getting a few errors that I do not know what they mean. I've been trying to solve the problems for a while now, but cannot get past these errors.

Line 12:

inventory.xsd:12:cvc-complex-type.2.4.a: Invalid content was found starting with element 'xsd:element'. One of '{"http://ift.tt/tphNwY":attribute, "http://ift.tt/tphNwY":attributeGroup, "http://ift.tt/tphNwY":anyAttribute}' is expected.

Line 14:

inventory.xsd:14:cvc-complex-type.2.4.a: Invalid content was found starting with element 'xsd:element'. One of '{"http://ift.tt/tphNwY":annotation, "http://ift.tt/tphNwY":restriction, "http://ift.tt/tphNwY":list, "http://ift.tt/tphNwY":union}' is expected.

Line 18:

inventory.xsd:18:cvc-complex-type.2.4.a: Invalid content was found starting with element 'xsd:attribute'. One of '{"http://ift.tt/tphNwY":annotation, "http://ift.tt/tphNwY":simpleType, "http://ift.tt/tphNwY":complexType, "http://ift.tt/tphNwY":unique, "http://ift.tt/tphNwY":key, "http://ift.tt/tphNwY":keyref}' is expected.

Here is the XSD:

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema elementFormDefault="qualified" xmlns:xsd="http://ift.tt/tphNwY">
 <xsd:element name="inventories">
  <xsd:complexType>
   <xsd:sequence>
    <xsd:element name="INVENTORY">
        <xsd:complexType>
            <xsd:sequence>
                <xsd:element minOccurs="0" maxOccurs="unbounded" name="BOOK">                
                    <xsd:complexType>
                    <xsd:attribute name="Instock" type="boolean" use="required"/>
                            <xsd:element name="TITLE" type="anyType">
                                <xsd:simpleType>
                                    <xsd:element name="SUBTITLE" type="anyType"/>
                                </xsd:simpleType>
                            </xsd:element>
                            <xsd:element name="AUTHOR" type="string">
                                <xsd:attribute name="Born" type="gYear"/>
                                <xsd:complexType>
                                    <xsd:sequence>
                                        <xsd:element minOccurs="1" maxOccurs="1" name="FIRST_NAME" type="anyType"/>
                                        <xsd:element minOccurs="1" maxOccurs="1" name="LAST_NAME" type="anyType"/>
                                    </xsd:sequence>
                                </xsd:complexType>
                            </xsd:element>
                            <xsd:element name="BINDING" type="string">
                                <xsd:simpleType>
                                  <xsd:restriction base="string">
                                    <xsd:enumeration value="hardcover"/>
                                    <xsd:enumeration value="mass market paperback"/>
                                    <xsd:enumeration value="trade paperback"/>
                                 </xsd:restriction>
                               </xsd:simpleType> 
                          </xsd:element>
                            <xsd:element name="PAGES" type="positiveInteger">
                                <xsd:complexType>
                                    <xsd:attribute name="FrontMatter" type="positiveInteger"  use="optional"/>
                                </xsd:complexType>
                            </xsd:element>
                            <xsd:element name="PRICE" type="decimal">
                                <xsd:simpleType>
                                    <xsd:restriction base="xsd:decimal">
                                        <xsd:minInclusive value="0"/>
                                        <xsd:maxInclusive value="100"/>
                                    </xsd:restriction>
                                </xsd:simpleType>
                            </xsd:element>
                            <xsd:element name="PUBLISH_DATE" type="gYearMonth"/>
                            <xsd:element name="ISBN" type="integer"/>
                            <xsd:element name="SUMMARY" type="anyType"/>
                    </xsd:complexType>    
                </xsd:element>
            </xsd:sequence>    
         </xsd:complexType>    
    </xsd:element>
   </xsd:sequence> 
  </xsd:complexType>  
 </xsd:element>    
</xsd:schema>

Thank you in advance.