You could try to display a captcha with the URL: http://yoursite/index.php?sec_img=144f3bbd
Do you see the captcha ? Any error messages in your logs ?.
The latest version of mythreads should have a captcha right? I installed and everything works, but the security code doesn't show up.
I ended up just adding my own captcha, but, the only way I could figure it out was to add a captcha system via javascript which I know isn't the best way because spammers can just simply turn javascript off.
So, I'm wondering if someone can tell me how to...