Ok perhaps I found a clue
Whenever I use the APPS program to download/install from the repository (which produces a failed status every time) there is an error entry in wm_errors file which states:
" md5sum: invalid option -- 's' "
running md5 check within APPS results in " OK "
Maybe this is why we don't see errors when using the command line " ab "
However " tce-load -wi " often results in md5 file not found