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I run several WP blogs on my servers, and this only happens to one of them. I’ve read several messages in these forums, but none seem to contain a solution that works for me.
None of the blogs use Twitter Tools plugin, I’m already running PHP 5.2.11 on the server.
When they were trying to publish a new entry, I noticed the following in the Apache logs:

192.168.0.91 – – [06/Jan/2010:01:19:58 -0500] “POST /~xxxxx/wp-admin/post.php HTTP/1.1” 403 876 (66) “http://www.xxxxx.net/~xxxxx/wp-admin/post-new.php” “Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.6) Gecko/20091201 Firefox/3.5.6 GTB6”

A 403 Forbidden error. Only we don’t see the 403 page. It goes to the page with the error. Here’s the call to that page in the Apache logs:

192.168.0.91 – – [06/Jan/2010:01:19:59 -0500] “GET /~xxxxx/wp-admin/css/install.css HTTP/1.1” 304 – (-) “http://www.xxxxx.net/~xxxxx/wp-admin/post.php” “Mozilla/5.0 (Windows; U; Windows NT 6.1;
en-US; rv:1.9.1.6) Gecko/20091201 Firefox/3.5.6 GTB6″

I’ve also tried disabling plugins, but that didn’t do any good either.
This all started with WP 2.9 and has continued in 2.9.1
Anyone have any other ideas as to a possible cause?

Thanks —