I try to use Exerb,but my exe failed to start

Ruby
1

DOS>exerb watch1.rb

and the output is watch1.exe

DOS>watch1.exe

C:\ruby\samples\FileSystemWatcher>watch1.exe
./filesystemwatcher.rb:1:in `require’: No such file to load – md5
(LoadError)
from ./filesystemwatcher.rb:1
from watch1.rb:4

Why exerb does not build require libs to .exe ??

any help would be greatly appreciated much.
Thanks a lot.

Warachet S.