# ActiveResource 3 on MRI 191: NameError (uninitialized constant Builder::XmlBase::Symbol)

**URL:** <https://www.ruby-forum.com/t/activeresource-3-on-mri-191-nameerror-uninitialized-constant-builder-symbol/188714>\
**Category:** Rails\
**Created:** [May 17, 2010, 2:45am UTC](https://www.ruby-forum.com/t/activeresource-3-on-mri-191-nameerror-uninitialized-constant-builder-symbol/188714 "2010-05-17T02:45:38Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![ylg](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/y/85e7bf/32.png) [@ylg](https://www.ruby-forum.com/u/ylg)\
**Post date:** [May 17, 2010, 2:45am UTC](https://www.ruby-forum.com/t/activeresource-3-on-mri-191-nameerror-uninitialized-constant-builder-symbol/188714/1 "2010-05-17T02:45:38Z")

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We’ve run into this before and, in this particular project, I’m  
positive we had a hack somewhere to get AR to work but it seems to  
have gone missing and I’m not finding any hints in git history or  
Google. Any call to an AR.create will trigger it. Seems like a  
strategically placed require or include did the trick but I’m probably  
misremembering.

The offending code in Builder is xmlbase:40:  
sym = “#{sym}:#{args.shift}” if args.first.kind\_of?(Symbol)

Why that method\_missing is firing off xmlmarkup:239 is a bit of a  
mystery to me, as 239 is just:  
\_ensure\_no\_block block\_given?

the backtrace:

builder (2.1.2) lib/builder/xmlbase.rb:40:in `method_missing' builder (2.1.2) lib/builder/xmlmarkup.rb:239:in`instruct!’  
relock/gems/activesupport-3.0.0.beta3/lib/active\_support/core\_ext/hash/  
conversions.rb:136:in `to\_xml’  
[…]

Any suggestions on stuff to try or look into?