If you want to use any web service in your application you have to add these lines in your 'config.xml' file.Otherwise you wont get permission to access those sites.Hope this helps :)
<access uri="http://www.address1.com" subdomains="true">
<feature id="blackberry.app" required="true" version="1.0.0"/>
<feature id="blackberry.invoke" required="true" version="1.0.0"/>
</access>
<access uri="http://www.address2.com" subdomains="true">
<feature id="blackberry.app" required="true" version="1.0.0"/>
<feature id="blackberry.invoke" required="true" version="1.0.0"/>
</access>