Fix fault in code the results in <xss....> database attack

I have had <xss...> database attacks on my site for a year. One of the people who looked at them said the problem was with the code of the membership company I'm using (SentryLogin.com). Here's a link to the code: https://www.sentrylogin.com/sentry/scripts/Sentry_AJAX.js. I need someone to go over the code the modify it to eliminate the <xss...> attacks on my databased. I will be $75 to anybody who can show me the fix in the next two days.