Error: uninitialized constant Mixpanel::Tracker::Encoding

[ahmed1490]

Basically Encoding::UTF_8 is not found.

⇒ rails s
/Users/Ahmed/.rvm/gems/ruby-1.8.7-p371@global/gems/mixpanel-4.1.1/lib/mixpanel/tracker.rb:144: uninitialized constant Mixpanel::Tracker::Encoding (NameError)
from /Users/Ahmed/.rvm/gems/ruby-1.8.7-p371@global/gems/mixpanel-4.1.1/lib/mixpanel.rb:1
from /Users/Ahmed/.rvm/gems/ruby-1.8.7-p371@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in 'require'
from /Users/Ahmed/.rvm/gems/ruby-1.8.7-p371@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in 'require'
from /Users/Ahmed/.rvm/gems/ruby-1.8.7-p371@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in 'each'
from /Users/Ahmed/.rvm/gems/ruby-1.8.7-p371@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in 'require'
from /Users/Ahmed/.rvm/gems/ruby-1.8.7-p371@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in 'each'
from /Users/Ahmed/.rvm/gems/ruby-1.8.7-p371@global/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in 'require'
from /Users/Ahmed/.rvm/gems/ruby-1.8.7-p371@global/gems/bundler-1.3.5/lib/bundler.rb:132:in 'require'
from /Users/Ahmed/workspace/railsApp/config/application.rb:7
from /Users/Ahmed/.rvm/gems/ruby-1.8.7-p371@global/gems/railties-3.0.20/lib/rails/commands.rb:28:in 'require'
from /Users/Ahmed/.rvm/gems/ruby-1.8.7-p371@global/gems/railties-3.0.20/lib/rails/commands.rb:28
from /Users/Ahmed/.rvm/gems/ruby-1.8.7-p371@global/gems/railties-3.0.20/lib/rails/commands.rb:27:in 'tap'
from /Users/Ahmed/.rvm/gems/ruby-1.8.7-p371@global/gems/railties-3.0.20/lib/rails/commands.rb:27
from script/rails:6:in 'require'
from script/rails:6