ASP: off per default. CAPTCHA: removed unneeded $admin. Filename: just convert chars like quote, doublequote, < > & to empty string.
Added some missing add_slashes(), get_post_escaped(), and strip_tags() for $_POST, $_GET and $_REQUEST-data. Also for $_SERVER['PHP_SELF'].
Text-captcha: moved text-file to database.
Security bugfix: Text file for text-captcha was readable from everywhere. Text-captcha: empty line in test file, following a question, was accepted as answer. Fixed.
Added missing keyword Id
Text-CAPTCHA: uses return() instead of exit() in case of error.
Text-CAPTCHA: added description how to input questions and answers.
fixed possible E_NOTICE-warning
Added Text-CAPTCHA on request. The captcha-text will be stored in temp/.captcha_text.txt