Broken Comments

Hello everyone. I’ve been scouring all sorts of support forums, and I cannot find a fix for what ails me. Basically, whenever I try to leave a comment on my site ( http://oldschoolgoth.com ) it lets names and email addresses be input into the fields, but when the comment is submitted, I get:
“Fatal error: Call to undefined function: wp_new_comment() in /home/oldscho1/public_html/wp-comments-post.php on line 51”

I’ve upgraded WordPress to 2.0.2, I’ve tried uploading different comments files from the WP installations, which have done nothing but break my site completely. I’ve had to restore from a backup and this is about as far as I can get with it. It all started when I got a few emails from my site letting me know there were 2 comments in moderation. Both of them were from a spammer, but ever since that day, nobody has been able to leave a comment, and it’s driving me bananas. Also, the spammer’s comments were never in my Awaiting Moderation spot, which I found to be odd, and never managed to be posted on the site.

I’m exhausted and at my wits end on this. If anyone has any ideas, please, let me know! I’m going to go chew through a desk now.