If you're working for an international company, you most likely won't run into any problems at work as a result of not speaking German. Day-to-day life is a different story, especially when dealing with government offices (which you'll be doing a LOT upon first arriving). English is not nearly as widely understood in Berlin as it is in other Northern European capitals, and I found the language barrier to be generally understated (that is, people claim it's easier to get by with English than it really is).