Collection fails even though the test says its ok...

I get this message after changing to 2.3

• Starting VM collector test
• Collection OK: 10.150.1.25. Start time: 2012-04-03 14:52:33 Duration: 2.948 seconds Samples: 332
• Ending VM collector test
• A collection from 10.150.1.25, begun at 2012-04-03 15:01:00, failed at 2012-04-03 15:01:03.

so, the test works fine, but when the real collection tries, it fails. And i don't see why.

i also get this message when trying to make rules:

the server cannot be contacted at this time.