This is most likely a problem with your BlackBerry server at work. check with your IT help desk.
There has been some recent news about BlackBerry outages outside the United States, but I believe that would only cause delays in your emails being sent and received, not actual connection errors to the BlackBerry service.
It's affecting BlackBerry users in the United States now too :
RIM "BlackBerry subscribers in the America may be experiencing intermittent
service delays this morning. RIM is working to resolve the situation as quickly
as possible and apologize to customers for any inconvenience. RIM will provide
a further update as soon as more information is available."