Getting error while server startup/for any ruby operation

Hi,

  I have ruby on my system.
  To get pdf report from the application, I searched in google and

got one gem and installed with their installation hints.
I extract the folder and in that a bulk of files like in ruby
folder with a read me file.
It ask me to run setup.exe.
I successfully did it.

  But, now I can't run the server.
  While Iam starting server/to do any ruby operation, it is showing

like follows.

  cmd>ruby
  ruby: invalid option -:  (-h will show valid options)


  Please help me, to clear this. What is this problem? How can i

clear it?