user id not fond

call activity

When I call a defined process p2 from the process p1, (which both of them work well independently) I get the following error message and process p2 fails:
Groovy script throws an exception of type class org.bonitasoft.engine.identity.UserNotFoundException with message = org.bonitasoft.engine.identity.SUserNotFoundException: USER_ID=0 | Can't find the user
and here is the script for business variable which is common between p1 and p2:
def businessObject2Var = new