From http://forums.pcper.com/showthread.php?t=440572

There seems to be a problem with optimized seti apps and boinc not getting new work during the current server difficulties. If you haven't got any new work for the last few days, try the following:

* Stop Boinc/Seti
* Rename app_info.xml so it won't be recognised
* Restart BOINC/Seti
* Let Boinc download the original SETI app - may not get through first time, but keep trying
* Wait until all transfers have finished
* Restore app_info.xml to original name
* Restart BOINC/Seti

You should at least have a decent cache of downloaded WUs now to crunch. Not sure if this will get "fixed" or if you'll have to do the same again when the cache runs dry if Berkeley are still experiencing problems.