Metasm is not working on 64 bit machine -Ruby 2.5 x64 installed

[bikashdash]

While i was trying to install the grinder i got the following error

C:\Grinder\node>ruby grinder.rb
Traceback (most recent call last):
5: from grinder.rb:9:in <main>' 4: from C:/Ruby25-x64/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in require'
3: from C:/Ruby25-x64/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in require' 2: from C:/Grinder/node/core/configuration.rb:6:in <top (required)>'
1: from C:/Ruby25-x64/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in require' C:/Ruby25-x64/lib/ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in require': cannot load such file -- lib/metasm/metasm (LoadError)
Metasm working as below

C:\Grinder\node>ruby -r metasm -e 'p Metasm::VERSION'
1

[bikashdash]

@stephenfewer Any idea what might be the reason ?