We've recently made a few changes to the greenfoot.org site - most notably, we've attempted to fix the double-post / multiple-post problem that happened with some browsers (when people got impatient and clicked the 'post' button more than once!!). It seems there was a resulting problem that you couldn't post in the forum at all if you were using the Chrome browser, but that should be fixed now. If you notice any problems with the site, please post here or send email to gallery@greenfoot.org. Thanks!