Aptana 3 ruby debugger - Exception in DebugThread loop: undefined method `is_binary_data?'

I'm trying to debug simple ruby file in Aptana 3. class HelloWorld def initialize() end def greet() puts "hello world" end end h=HelloWorld.new h.greet breakpoint is set to h.greet after I started debug, debugger starts, but when it tries to initialize ruby class, debugger disconnect with message Fast Debugger (ruby-debug-ide 0.4.9) listens on :54749 Exception in DebugThread loop: undefined method