I was suffering the same problem for days, I can tell you what worked for me. There is a .xml file called "updateservers.xml" in your planeshift directory which is usually C:\Program Files\Planeshift in windows. I apologize, but I'm unsure how to do this on any other OS, perhaps you can simply locate the file on your OS (which I've never heard of lol). It seems to be the file that points to the update server that Planeshift will use. It is currently set to the "ss9" server which is not functioning.
You need to open this file with notepad by right-clicking it and mousing over "Open with" then selecting "Notepad" from the list.
You will see:
<mirrors>
<mirror id="1" name="ss9" url="
http://updater.s99 etc etc (I forgot the exact URL)" />
</mirrors>
Simply delete all the information and replace it wiith this:
<mirrors>
<mirror id="1" name="sajut" url="
http://updater.sajut.de/update/" repair="true" />
</mirrors>
Then reload Planeshift and it should update for you.
CAUTION: I believe this server is temporary.
Don't forget to copy the updateservers.xml file and paste it elsewhere so that you wont have to completely reinstall to regain the previous server information. I've been able to update and enter into the game this way.
I hope this works for you.