1) i'm using GWT 2.5.1, It should be supported since it's greater than 2.0
2) the application is compiled with java 1.6 (64 bit), as explained by the docs I replaced the JRE of loadrunner (should be 1.5) with the one I'm using before capturing the logs
3) the jars should be fine, I recreated them a couple of times (just to be sure) and I've also tried decompressing the .war and asking loadrunner to point directly to the directory containing the rpc and classed files but nothing changes
should I check for something specific in the logs in order to have an idea of the cause of the problem?