Yet another sidebar in FireFox issue

I’ve been cruising these forums for a month or two trying to sort out my issues with my sidebar in Firefox– like loads of topic-starters here, mine drops down to the bottom rather than floating nicely (though it looks perfect in IE).
-I’ve tried resizing all images, which didn’t work, so I got rid of them entirely. Still didn’t work (So I put them back). I’ve removed all widgets from my sidebar, so as to avoid any java getting in the way, still no good (These, I didn’t put back).
-I’ve tried adding a line of code to the CSS that begins with “fix” and goes on to tell it to… stop floating, I reckon. It was suggested to another complainer last year and apparently worked for them.
-I’ve tried changing the size of the wrap section of the css, and both the right and left columns to make sure there’s room for everything, in various combinations. No good.
-I’ve validated all the code– it checks out. I imagine I’m missing something the validators can’t find, which needs a human touch. And I’m not on it.

It works sometimes when I load it, but 70% of the time it’s mucked up.

I’d really appreciate any help you can offer. The site is kvtaylor.com, in case anyone wants to have a look. A friend adjusted/created the theme for me, so I confess I’m trying to work with someone else’s code, which puts me at a serious disadvantage. That and I’m a newbie at this, myself. Obviously.