Rake failures in assert_tag in Typo 4.0.2 on Dreamhost

(cross-posted in the old Ruby on Rails google group -- sorry!)

I've got Typo 4.0.2 running beautifully on my Dreamhost server, but there are these nagging failures when I run rake that are annoying me. Everything seems to be working just fine from the front-end, so it's not super critical. But it bugs me that I can't get rake to pass. What's even wierder is that the tests pass 100% on my local machine (windows).

It looks like all the errors have to do with assert_tag. By looking at the errors from rake I don't see anything wrong, so I think could assert_tag be broken in my installation of rails?

Here's three of the 7 failures that I get consistently (the other ones are more of the same and are really long):

1) Failure: test_full_post(Admin::ArticlePreviewTest) [./test/functional/admin/article_preview_test.rb:61]: expected tag, but no tag found matching {:child=>"An extension", :after=>{:child=>"A body", :after=>{:content=>nil, :tag=>"h4"}, :tag=>"p"}, :tag=>"p"} in: "<h4>A title</h4>\n\n<p>A body</p><p>An extension</p>\n". <nil> is not true.

2) Failure: test_only_body(Admin::ArticlePreviewTest) [./test/functional/admin/article_preview_test.rb:37]: expected tag, but no tag found matching {:child=>"A body", :after=>{:content=>nil, :tag=>"h4"}, :tag=>"p"} in: "<h4></h4>\n\n<p>A body</p>\n". <nil> is not true.

3) Failure: test_only_extended(Admin::ArticlePreviewTest) [./test/functional/admin/article_preview_test.rb:47]: expected tag, but no tag found matching {:child=>"An extension", :after=>{:content=>nil, :tag=>"h4"}, :tag=>"p"} in: "<h4></h4>\n\n<p>An extension</p>\n". <nil> is not true.

Anybody have a clue? I have searched and searched and haven't seen anything about this.