使用 RubyMine debug 的时候出错，错误信息如下：

/Users/apple/.rvm/rubies/ruby-1.9.3-p125/bin/ruby -e at_exit{sleep(1)};$stdout.sync=true;$stderr.sync=true;load($0=ARGV.shift) /Users/apple/.rvm/gems/ruby-1.9.3-p125@global/gems/ruby-debug-ide-0.4.17.beta16/bin/rdebug-ide --debug --port 49842 --dispatcher-port 49843 -- /Users/apple/al/practice/merge_sort.rb
Fast Debugger (ruby-debug-ide 0.4.17.beta16, ruby-debug-base19x 0.11.30.pre11) listens on 127.0.0.1:49842
Connected from 127.0.0.1
37984: Starting control thread
37984: Processing in control: b /Users/apple/al/practice/merge_sort.rb:40
37984: <breakpointAdded no="1" location="/Users/apple/al/practice/merge_sort.rb:40"/>
37984: Processing in control: b /Users/apple/al/practice/merge_sort.rb:39
37984: <breakpointAdded no="2" location="/Users/apple/al/practice/merge_sort.rb:39"/>
37984: Processing in control: b /Users/apple/al/practice/merge_sort.rb:41
37984: <breakpointAdded no="3" location="/Users/apple/al/practice/merge_sort.rb:41"/>
37984: Processing in control: start
37984: Starting: running program script
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
[1, 2, 4, 8, 9, 22, 22, 33, 333, 333, 33333]

Process finished with exit code 0

求解决。。。