BB Curve AIM says I'm not responding to messages

I have my AIM status as "AVAILABLE", but whenever someone send me an IM, I'll automatically respond with "I'm not responding to any messages right now."

I don't know how to take this away. When I log into my PC at home, I notice the same message is in my status box. I can change it for that session, but it will always come back once I log off.

Also, sometimes I'll get IMs and the message will appear in the message section of the BB, but when I go to the actual conversation, my friend's message would not appear.

I'm not sure if this is the AIM being a problem as a whole, or what. Is there any way for me to get a better AIM?