Hello,
Thank you for the answer.
In fact, in the meantime I found the solution for me.
In my case, I was instanciating the HornetQTaskClientConnector with always the same name "client" (I mean the same value for the first parameter called name).
By luck, I saw an example of code somewhere using a different name for each HornetQTaskClientConnector by adding a randomly generated id to the "client" string.
Doing that the error disappeared and everything went well.
So for sure it is too late for you but I provide my answer in order maybe to help someone else.
On my side, even with this solved issue, I am still wondering if I am going to use jBPM or develop my own simple specific Java code because all these embedded frameworks are generating some strange errors really not easy to diagnose. I think nowadays there are too many frameworks embedded in frameworks (!) or applications... and it is adding a real complexity to a lot of things. This complexity is usefull or not, this is the debate...
Jena