synchronisation problem between live2 and my sampler

[frizouille]

i've got a problem with my config. I use a sampler electribe es1 with ableton live (in slave). When I push the play button of my electribe, live start correctly and the synchro is good but when I push on stop button on my es1 and play again, the samples into live don't restart at the start point of the samples (ex it start in the middle of the sample).
the problem is sometimes it works and sometimes it doesn't arrrrrghhh .

So if you encountered this problem tell me
Thanks everybody