Help with my BlackBerry needed please?

[Vanessa]

Hello,
So recently I've changed my Blackberry Curve 9300 for a Blackberry Torch 9800, I've had my sim card in, which is on contract, I didn't experience any problems with BBM or Twitter or the Internet, but however I've switched back to my old Curve for various reasons and it took about an hour to get the BBM working properly again, I've put my media card in, basically everything works perfectly such as media, or calls, texts, Blackberry Messanger (BBM) and even my Browser, as I am on contract which allows me to go on pretty much everything, but however my Twitter app does not work properly and when I try and sign in, it comes up with this message 'You are currently on a data plan that does not support this application.if you want to use this application, please connect to a Wi-Fi network or contact your service provider to upgrade your date plan' This is what it displays, before I switched phones, it worked perfectly, and it don't need to upgrade my data plan, I don't see why it won't work it this phone again, it worked on my Torch when I used it. Also I cannot access Blackberry App World.
It displays this 'Blackberry App World is having trouble connecting to thr Blackberry App World server. Verify your network connections and try again' what does this mean? I never had problems like these, I never had to use Wi-Fi or such. And I have full signal, so what might be the problem? Do I have to ring up my network company or something? If so, what do I say?
Many thanks for your time
Urgenty needed to be fixed

[Joe]

well the message is basically saying your not connected to the blackberry data plan. try a hard reboot, remove battery with phone on, wait a few seconds then replace. if that does not work then call your network.