More Karma for Cyberion for a detailed and well-written response on the Data Receiving Error monster (sadly NOT a rare mob lately). Do you play on Lailah, and do you have a guild?
Sorry angelhoney, haven't heard of that specific bug with objects not appearing in-game. Langerz and others have collected some great general info to which he's posted links. I personally don't think this indicates a problem with any security software, but I've been wrong before. Once
If you're now able to connect and play, and the issue is not seeing objects in-game, I'd echo the advice of others here and verify that you've got the most recent drivers for your video display system. Good luck!