Loosing RosterItems after a while

I created a Pluing which gets connected to my System Database, and based on this data I create Users and its Rosters… and I add Roster Items to it.

Also, I have a client using the Winfessor XMPP client library to connect to the jabber server.

Initially everything looks cool, I have presence for everyone and all is happiness, debugging I can see the XML messages where the client resquests for the Roster and it gests replied with the Roster (and its rosterItems in it) for example:

SENT <iq id=“b96d50f1-9b80-4117-ace9-e0bed5e70308” type=“get”><query xmlns=“jabber:iq:roster” /></iq>

RECEIVED <iq type=“result” id=“b96d50f1-9b80-4117-ace9-e0bed5e70308” to="9725552101@example.com/MMA_CHAT"><query xmlns=“jabber:iq:roster”><item jid="9725552101@tekelec.com" name=“SwissFirst SwissLast my customer” subscription=“both”/><item jid="9725552102@example.com" name=“John Locke my customer” subscription=“both”/></query></iq>

After a several hours, I noticed this leaving it running during the night, when I come to it in the morning I do not have presence anymore. However If I see the Admin Console, I can see my users and the Sessions for all of them. I do check the client log files and I see that when it requests for the Roster, the reply from the Jabber server is empty, it gets the response but it has no items in it. example:

SENT <iq id=“f0864d97-b4ba-4c23-8dfd-bc523d6019c5” type=“get”><query xmlns=“jabber:iq:roster” /></iq>

RECEIVED <iq type=“result” id=“f0864d97-b4ba-4c23-8dfd-bc523d6019c5” to="2144511123@engdba.genband.com/MMA_CHAT"><query xmlns=“jabber:iq:roster”/></iq>

As you can see the response comes empty… I am assuming this is the reason I do not get presence in my client.

So the question would be… What might be the reason I am not getting the RosterItems ? Is the Jabber Server loosing them ?

(my users and session look alright in the Jabber Admin Console)