Whether Silvio was faking to be sick or not, Paulie did still screw up when collecting the dough. I think what happened in the Pine Barrens was this; The Russian climbed up in a tree, despite being shot in the head and after that, he climbed down and lost conscience. Later on, the Boy Scouts find the body and call Slava, as Chase stated in the interview. The new mystery here is, why did Slava never confront Tony about this?