3dttest is an old program (dating to late 1994), and as such, wasn't written to support multiple values per voxel in a single dataset. You are trying to put in multiple values at each voxel from one dataset with your '-set2 Log*' option -- but the program can't handle that.
Ideally, we would re-write 3dttest to allow what you want to do, but at the moment that seems unlikely since we are extremely busy.