The message "DL is deprecated, please use Fiddle" is not an error; it's only a warning.
Solution:
You can ignore this in 3 simple steps.
Step 1. Goto C:\RailsInstaller\Ruby2.1.0\lib\ruby\2.1.0
Step 2. Then find dl.rb and open the file with any online editors like Aptana,sublime text etc
Step 3. Comment the line 8 with '#' ie # warn "DL is deprecated, please use Fiddle" .
That's it, Thank you.