Um, dare I say it? fourth time lucky?
Lots of fixes;
Bots should now be a bit keener to play!
Strange -ve message length problem sorted - think this might have been the main problem!
Message passing improved.
User names can now be 3 characters (just for you Mac!).
I also tidied the load screen a bit.
You now start with 30 credit - not sure if this is a good change or not…
EDIT: Hold on - it’s crashed again… 
Humph! Error;
com.google.appengine.api.datastore.DatastoreTimeoutException: Unknown
leads me to;
GAE's session handling is backed by both the datastore and memcache. App
Engine's datastore is built on Big Table, which is a very large, distributed
DBMS. Because of its distributed nature, you will likely see a small amount
(generally 0.1 to 0.2 percent) of datastore operations fail over time. We
are constantly making improvements to App Engine's back-end to drive this
percentage even lower, but if you depend on sessions to manage your
application's state, you should definitely be aware that there is the
potential for failure and appropriately handle any exceptions that get
thrown in the event of a datastore issue.
In other words, I can never be sure if a message has been stored or not!
Pass me that crowbar - I’ll see if I can get a rollback system in there…