WP v2.1 has issues with post.php and post-new.php

I dunno when this happens, but as soon as I get the same error again, I’ll post it here.
The problem is, WordPress sometimes thinks post.php is the – wait, I think I got it! The problem may be – no no, it has to be it! The problem is (I think), when WP autosaves the post, and after that, when you publish it, WP gives this error:

https://img443.imageshack.us/img443/5598/aha1lx.png

And even you say yes, it still does not post the post (posting the post, interesting). And when you go back tow times in your browser (I use Firefox), you won’t find the post you just wrote.

Yeah, OK, even I didn’t understand the message I just wrote ?? Let me summerize: When the autosaving happens, WP thinks that he’s (or she’s, I dunno the gender of WP) in the post.php page. I found these suspicious lines in these files:

1. wp-settings.php > line 159: require (ABSPATH . WPINC . '/post.php');
2. wp-admin\dbx-admin-key.js.php > line 6: case 'post.php' :
3. wp-admin\edit-form-advanced.php > line 10: <form name="post" action="post.php" method="post" id="post">
4. wp-admin\edit-form.php > line 4: <form name="post" action="post.php" method="post" id="simple">

I forgot to ask though, does this problem happen at your blog, too?