REXML file load 2 minutes Rails 3/1.9.2 while <1second Rails 2.3.8/1.8.7

I have a class and test for it which was running reasonable fast in Rails 2.3.8/Ruby 1.8.7 (1 second)

Now that I have updated this app to Rails 3/1.9.2, the same test takes 4 minutes!!!

I have honed in on the slow code which is where REXML loads a pretty short xml document:

@mismo_file = mismo_xml_file

This line takes just short of forever whenever it is hit. What could it be doing? I am wondering if there are any others who have encountered the same problem or a way to solve it. Everything else (the document, the computer, and my own code) is a constant, the Ruby and Rails v’s are only differences.