I use the play-gae module.
I tried to delete this jar from lib directory => error 500 during execution (ClassNotFoundException: com.google.appengine.api.memcache.MemcacheServiceFactory).
So, it seems that this jar is necessary…
I find a discussion about this here : http://groups.google.com/group/play-framework/msg/d103ebc5a789efc1 but no solution.
I must split this jar ? Pfff… 😉 Everybody do that ?
Maybe you can try to use a separate install of GAE with a more recent version. I have version 1.5 installed and I’m uploading my app without error: