can't debug using rubymine

the process works fine on command line , when I tried to debug it using rubymine it get stuck or simply quits.

I tried to run the process from command line and attach rubymine to it (attach process) but got 

gems/ruby-debug-ide-0.4.28/lib/ruby-debug-ide/command.rb:56:in `method_missing': undefined method `has_key?' for nil:NilClass (NoMethodError)

from /Users/joseph/.rvm/gems/ruby-1.9.3-p551/gems/ruby-debug-ide-0.7.0.beta6/lib/ruby-debug-ide/greeter.rb:22:in `print_greeting_msg'
from /Users/joseph/.rvm/gems/ruby-1.9.3-p551/gems/ruby-debug-ide-0.7.0.beta6/bin/gdb_wrapper:77:in `<main>'

I have no license and I don't know if to buy one if it continues.

help please.

thanks

joseph