Wiki

I'm running moodle 1.5 and have downloaded the latest wiki, and am having some problems with formatting.  I teach computer science, and my students need to be able to post code.  I'm running into a few problems I haven't had before.

when trying to display this line:

while ( i <= 20 )

the display stops after the i, and nothing else shows.

I don't know if this is related, but we've also lost our formatting bar, like the one on this window.  I've tried the <pre> and <code> and even <nowiki> tags and still no success.  I'd like this wiki to be a simply WYSIWYG format, so the students can post questions about code, and answer using code.  I can't find a setting to turn on the formatting bar- I'd like to not use any wiki code features, like linking, etc, as we use [ ] a great deal in our code as well.  I generally use the HTML only setting, but something is very wrong.

Can anyone help?  I'm trying to get this setup for exam reviews this weekend.