WordPress Plugin: Old Core Files

I saw the Old Core Files plugin advertised on my WordPress dashboard & I was curious to see what it’d report for this instance.
It listed 461 obsolete files which I was unable to delete but this may be due to my config rather than a plugin issue (fiddling with filesystem permissions did not help). After the tidy up I went to compose a post only to find that leaving the plugin active breaks the add new post section of WordPress, the following error message is logged

2013/01/27 21:46:36 [error] 49410#0: *511 FastCGI sent in stderr: "PHP Fatal error: Call to a member function abspath() on a non-object in /myblog/wp-content/plugins/old-core-files/old-core-files.php on line 237" while reading upstream, client:, server: http://www.myblog.foo, request: "GET /wp-admin/post-new.php HTTP/1.1", upstream: "fastcgi://unix:/tmp/php.socket:", host: "www.myblog.foo", referrer: "https://www.myblog.foo/wp-admin/"

If you have an instance of WordPress that’s been around for a while & has gone through several version updates then it’s well worth installing as a one off. Use the plugin to get a list of obsolete files & remove the plugin afterwards. The current version (v1.0) seems to cause issues if left enabled.

Update 28/1/2013
Version 1.1 has been released which removes the delete button.