add in another ERROR for wrong FILE=, also allow rake run_one FILE=real-world/bm_hilbert_matrix.rb to work
add in another ERROR for wrong FILE=, also allow rake run_one FILE=real-world/bm_hilbert_matrix.rb to work

acangiano/ruby-benchmark-suite,acangiano/ruby-benchmark-suite,acangiano/ruby-benchmark-suite,acangiano/ruby-benchmark-suite,acangiano/ruby-benchmark-suite,acangiano/ruby-benchmark-suite,acangiano/ruby-benchmark-suite,acangiano/ruby-benchmark-suite