The problem is related to importing the schema files.

Replacing the following lines

<import namespace="http://webservices.sabre.com/sabreXML/2003/07"
location="EndTransactionLLSRQRS.xsd"/>
<import namespace="http://www.ebxml.org/namespaces/messageHeader"
location="msg-header-2_0.xsd"/>
<import namespace="http://www.w3.org/2000/09/xmldsig#"
location="xmldsig-core-schema.xsd"/>
<import namespace="http://www.w3.org/1999/xlink" location="xlink.xsd"/>
<import namespace="http://schemas.xmlsoap.org/soap/envelope/"
location="envelope.xsd"/>
<import namespace="http://www.w3.org/XML/1998/namespace"
location="xml.xsd"/>
<import namespace="http://schemas.xmlsoap.org/ws/2002/12/secext"
location="wsse.xsd"/>

with

<types>
    <xs:schema
targetNamespace="http://webservices.sabre.com/sabreXML/2003/07">
        <xs:include schemaLocation="EndTransactionLLSRQRS.xsd"/>
    </xs:schema>
    <xs:schema
targetNamespace="http://www.ebxml.org/namespaces/messageHeader">
        <xs:include schemaLocation="msg-header-2_0.xsd"/>
    </xs:schema>
    <xs:schema targetNamespace="http://www.w3.org/2000/09/xmldsig#">
        <xs:include schemaLocation="xmldsig-core-schema.xsd"/>
    </xs:schema>
    <xs:schema targetNamespace="http://www.w3.org/1999/xlink">
        <xs:include schemaLocation="xlink.xsd"/>
    </xs:schema>
    <xs:schema targetNamespace="http://schemas.xmlsoap.org/soap/envelope/">
        <xs:include schemaLocation="envelope.xsd"/>
    </xs:schema>
    <xs:schema targetNamespace="http://www.w3.org/XML/1998/namespace">
        <xs:include schemaLocation="xml.xsd"/>
    </xs:schema>
    <xs:schema
targetNamespace="http://schemas.xmlsoap.org/ws/2002/12/secext">
        <xs:include schemaLocation="wsse.xsd"/>
    </xs:schema>
</types>

and downloading all required schema files from
http://webservices.sabre.com/wsdl/sabreXML1.0.00/tpf/ to the same directory
where EndTransactionLLSRQ.wsdl  is located will enable stub generation. The
required files are:

EndTransactionLLSRQ.xsd
EndTransactionLLSRQRS.xsd
EndTransactionLLSRS.xsd
env.xsd
envelope.xsd
msg-header-2_0.xsd
wsse.xsd
xlink.xsd
xml.xsd
xmldsig-core-schema.xsd

There will be some validation warnings about duplicate global attributes; it
will probably be worthwile to fix them.

Thanks,
Yuri