# Rubygems.rb:87: uninitialized constant Gem::Mutex (NameError)

**URL:** <https://www.ruby-forum.com/t/rubygems-rb-uninitialized-constant-gem-mutex-nameerror/128487>\
**Category:** Ruby\
**Created:** [February 8, 2008, 1:01am UTC](https://www.ruby-forum.com/t/rubygems-rb-uninitialized-constant-gem-mutex-nameerror/128487 "2008-02-08T01:01:47Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Charles\_Hoffman](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/13edae/32.png) [@Charles\_Hoffman](https://www.ruby-forum.com/u/Charles_Hoffman)\
**Post date:** [February 8, 2008, 1:01am UTC](https://www.ruby-forum.com/t/rubygems-rb-uninitialized-constant-gem-mutex-nameerror/128487/1 "2008-02-08T01:01:47Z")

</div>

Hi folks,  
I’m trying out code examples from Pickaxe 2nd ed. using the regular Ruby  
interpreter running on WinXP, and editing/running via RDT in Eclipse.  
Examples from the chapter on multithreading are giving me this error  
message – though after displaying it, the program seems to run fine.  
Any thoughts on this?

---

<div class="post-metadata">

**Author:** ![Charles\_Hoffman](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/13edae/32.png) [@Charles\_Hoffman](https://www.ruby-forum.com/u/Charles_Hoffman)\
**Post date:** [February 8, 2008, 7:54pm UTC](https://www.ruby-forum.com/t/rubygems-rb-uninitialized-constant-gem-mutex-nameerror/128487/2 "2008-02-08T19:54:02Z")

</div>

It would help if you actually posted ur code