do the entities have an @Version on the anywhere? you probably should be using that.
Ok thanks, since I use seam-gen to generate the JPA from the mysql database, all I had to do is add a version INT column to my tables.
The hibernate reverse engineer then automatically added @Version.
Although I am not happy that this sort of thing is so ... undeclared, the names of table columns and tables is important. For example I can't have a column called content, it causes problems. Theres a few other table restrictions for their names.