I installed Hashcash on my weblog recently. It works great, but on opening a new browser instance the following error is pre-pended to the page output (gzip is 'on' in WordPress settings):
<tt>ob_start(): output handler 'ob_gzhandler' cannot be used after 'URL-Rewriter' in /home/ [snip] /wp-includes/functions.php on line 585</tt>
This happens on individual post pages and monthly archives. Oddly enough, doing a hard reload (Ctrl+F5) makes this error message disappear. (Running on Firefox 1.0.6 on Ubuntu 5.04.)
I'm not sure this is Hashcash's fault, but it did start happening after I enabled Hashcash. I've now disabled gzip on my blog (thereby making the problem go away) until I figure out why this occurs.
Any tips to fix this would be appreciated. Thanks!