I see me too the "Unexpected error. Please refresh the page try again later" when I try to perform the process "less to css".
But this error shows only on the live site, not on the local one (althoght they are absolutely identical).
My question is: if I compile locally less to css, then what are the modified files to upload on the server?
Perhaps the entire "t3_bs3_blank/css" folder?
Or also the "t3_bs3_blank/less" folder?