Can't Post on Message Board

[oandic]

Script URL: http://m3-forum.comxa.com/mboard
Version of script: 1.3
Hosting company: http://000webhost.com
URL of phpinfo.php: http://m3-forum.comxa.com/mboard/phpinfo.php
URL of session_test.php: http://m3-forum.comxa.com/mboard/session_test.php
What terms did you try when SEARCHING for a solution: Searched on PHP Junkyard and Google

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I am not able to post on my message board. When I try, after entering the captcha I'm automatically sent to http://error404.000webhost.com/? I've also tried with different browsers with no luck. But an interesting thing, when trying with firefox the captcha is always the same, while on different browsers it changes in every trial.

I've uploaded everything according to the readme file (image folder as binary and the rest as ASCII), edited the permission settings for the "msg" folder and count, threads files.

What may be the problem?
Thanks in advance!

[oandic]

I solved the problem. It seems I made a stupid typo somewhere...