my extension's update doesn't seem to work

Hi all,

I had a text field in my extension which had some default value , say
value1. Now, I changed it to have default value as "maulin vasavada"
and rebuild the XPI file.

I have created the update.rdf file and put on my Tomcat and configured
the mime-type for .xpi in my tomcat4.1's web.xml. Also, I made sure
that it is going to my server when I click on "Update" by stopping the
server and running into the error.

I hope I am having correct update.rdf content. Here it is,
<?xml version="1.0"?>

<RDF:RDF
xmlns:RDF="http://www.w3.org/1999/02/22-rdf-syntax-ns#"xmlns:em="http://www.mozilla.org/2004/em-rdf#">

<RDF:Description

about="urn:mozilla:extension:{68dcf04d-e048-40cc-9347-673c28aac8ef}">

<em:updates>
<RDF:Seq>
<RDF:li

resource="urn:mozilla:extension:{68dcf04d-e048-40cc-9347-673c28aac8ef}:0.1"/>

</RDF:Seq>
</em:updates>

<em:version>0.1</em:version>

<em:updateLink>http://mytomcat:8080/test/myext.xpi</em:updateLink>

</RDF:Description>

<RDF:Description

about="urn:mozilla:extension:{68dcf04d-e048-40cc-9347-673c28aac8ef}:0.1">

<em:version>0.1</em:version>

<em:targetApplication>
<Description>

<em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384}</em:id>

<em:minVersion>0.8</em:minVersion>

<em:maxVersion>1.2</em:maxVersion>

<em:updateLink>http://mytomcat:8080/test/myext.xpi</em:updateLink>

</Description>
</em:targetApplication>
</RDF:Description>
</RDF:RDF>

Do you see any problem with this update.rdf? How do I make sure
"Update" functionality works for my extension (before I give it to
people and they can't update it).

Thanks
Maulin