Have you found there is a problem with Twitter on your Blackberry if you are using UberTwitter or on your android phone using Twidroyd? Then the reason is that Twitter has suspended them for violation of their terms of business.
They announced: “We have suspended UberTwitter and twidroyd for violating our policies. Every day, we suspend hundreds of applications that are in violation of our policies. Generally, these apps are used by a small number of users. We are taking the unusual step of sharing this with you because today’s suspension may affect a larger number of users.”You can download the official Twitter for Blackberry, Twitter for Android and other official Twitter apps here.
You can follow Twitter support here.