Redmine

Hi all !

I had download BitNami Project for Windwows, after that i had go to e:\BitNami directory witch is my main dir. After that i wrote "ruby script/generate redmine_plugin Nari" but the cmd said: 
"ruby is not recognized as an internal or external command..." I really don't understand why ? Because the Bitnami had installed the Ruby to my OpSys.
 If i go to the ruby/bin and recommand the Opsys it said: "no such file or directory script/generate" 
 Can anyone help me please ? What should I do ?
Thx: Károly