Error -118

I have been having this issue since I updated Steam the other day. When I am downloading a game, I cannot surf the internet, nor can I access the Steam store via the gui. When I do try and access the store, I get a error -118. However, when I pause all Steam downloads, I can then reaccess the store and surf the internet via my browser. I have tried reinstalling the update but no joy. Does anyone know how to rectify this at all?

Thanks