in Ovi Contacts, if you add / invite someone who is using google apps for your / their domain to chat in all likelihood you will hear nothing back no matter how many times you send an invite.
however this is not an ovi problem but a google apps / dns problem. turns out some SRV (location of service) records need to be created in your / their DNS.
this help topic from google explains what your friend needs to do to enable xmpp with anyone outside of google
apparently this document is not quite complete and you / they also need to add the following SRV entries to their DNS
hope that helps - took me months to figure out what was wrong!