XML is so picky!

The reason my blogroll wasn't hot is because I forgot that XML is so picky. 
Here's what happened.  I have been using Newsgator, and since it exports in OPML
I decided to export, do a little massaging, and then use it in BlogX.  Cut and
paste and there it was in my blog in all it's glory.  And I forget to test it. 
(Bad Laura, Bad!)  Once I get to work this morning, I look and look at the OPML
and it looks fine to me.  I reduce it down to one entry.  Still not hot. 
Simplify that entry down, still not hot.  Finally I give up and ask Andy Oakley
for a sample from a BlogX blog that works.  He generously sends me the starting
point file (the one that has ChrisAn in it, surely you've seen it), and mentions that
it might be a case sensitivity problem. 

And there it was.  Duh. BlogX wanted htmlUrl and xmlUrl and Newsgator exported
htmlurl and xmlurl. What a pain. Why is there case sensitivity in XML? 
I just don't get it.