It may be not your problem but this same error happened if you are with Java and using GAE SDK 1.5.5 because Google included jar datanucleus-appengine.1.0.9 by mistake (where XG transactions are not supported). They notice and ask you to update that jar to datanucleous-appengine.1.0.10final , you can find it here<http://code.google.com/p/datanucleus-appengine/downloads/detail?name=datanucleus-appengine-1.0.10.final.jar&can=2&q=> .
Another reason may be that XG transactions are limited to operations between a max of five entity groups, but I don't know if this is the exception returned in that case. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To view this discussion on the web visit https://groups.google.com/d/msg/google-appengine/-/N9zCf7c6D7MJ. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en.
