177453 CAPTCHA added to cgi

DO NOT BID IF YOU DON'T HAVE A LINUX MACHINE TO DEVELOP THIS ON, OR DO NOT KNOW LINUX ***VERY*** WELL! I cannot walk every programmer out there through this. I'm looking for someone I can COUNT ON for ongoing work. The project; Small job, quick job for someone knows what they are doing. This is the THIRD time I've posted this one. It's a SMALL job and I keep getting promises and no deliveries from people who THINK they are programmers. I am using a small open source CGI tool for automated sign up to my email services. I need this modified to allow for a CAPTCHA challenge to prevent spammers from using robots. Almost any open source captcha tool could be used. My servers have perl/php installed on them. However, what ever you do use, it must be stand alone, not dependant on having to install a number of additional things on the server, so that I can copy it to my other servers without having to install a number of support packages. The CGI calls up an HTML page which resides in /cgi-bin/html. It is this HTML page which needs to have the captcha installed. I'm looking for something SAFE and SECURE so please, enough with the NEW programmers. I need someone who knows what he/she is doing. Thank you.