On 17/11/2009, at 11:00 PM:

Re: dyld: Symbol not found: _rb_intern2?TM blogging bundle
     error

[?]
I have reverted the contents of /usr/local to a backed up copy, and  
now I'm running the default SL ruby 1.8.7. Unfortunately I still get  
the same issue.

It would appear that you didn?t fully revert what you did.

You're right, I don't think I did. Unfortunately I think I stuffed a few things
up, and so this gave me an excuse to do what I've been meaning to do
for a little while, and reinstall SL (maybe not the best way to fix the issue,
but hey it worked).

There are problems with a custom built ruby on Snow Leopard?.

Did you delete /usr/bin/ruby? And if so, is the thing you restored  
from backup the version from Snow Leopard, or just your own build of  
1.8.7?

If you did delete the system ruby, are you aware that there is also / 
System/Library/Frameworks/Ruby.framework?

From what I could tell I was using the binary of ruby that you mention:
I didn't delete /usr/bin/ruby, but it was symlinked to the one in Ruby.framework.
In fact that was never changed, my custom build of ruby was using
/usr/local/bin/ruby. I'll have to make sure in the future my custom builds
are isolated so that I can easily revert if issues arise.