Same problem here, and opening up safari to a page fixed it as well.
Just to give a little more detail, it's definitely some sort of
internal caching because the issue happened immediately after I
switched back to radio (3G) from using my local wireless. Before
wireless it worked fine, on wireless it worked fine, then switching
back to 3G caused the choke... it refused to start any connections and
posted the same error as above. This leads me to believe it's still
using whatever cache it got from the wireless connection. Note:
restarting the phone did not solve the issue, only loading a new page
in safari did.