Ok, that's weird. VolPex sent me a WU wich i should finish with a time limit of 14 minutes ago. And just when the WU starts running it finishes with a misscalculation. Any idea of what happened?

Nothing new... That is how they ALWAYS send out their work.
Each active task immediately takes over 1 core your PC until it's run is completed.
The tasks need a CONSTANT internet connection to run and receive credit.

ALL TASKS will show as COMPUTATION ERROR when completed even if they completed successfully.

Appears they have NOT fixed an on-going problem - See my post ALL REMD Protein Folding v1.35 TASKS FAILING WITH "Child client failed to connect" over at their forum.
As you can see by browsing their forums, there IS A LACK OF COMMUNICATION FROM THE PROJECT'S ADMINS.

This is easily contradicted by the number of people who have credits for this project (1,695).
Just that there is a problem at present doesn't mean that all tasks will fail at all times.