When I bought my first AntMiner, the guy I bought it from warned me to always make sure I put a password on each worker, even if it's not required by the pool.  He said he had trouble with his until he had added a password.  I'm not sure if this is true...I've just always put passwords on them.

Also, make sure there are no spaces at the end of the end of the worker name.  I couldn't connect once and that turned out to be the problem.