There are often problems with the FP extensions. They were a nightmare in FP 97, improved a bit in FP 98 and seem to have gotten worse again with FP 2000. Since they are only needed for interactivity and since cgi scripts work much better than FP interactivity it is recommend that people only use FP for static pages. (Hover buttons, animated transitions and similar goodies are not really interactive and will work fine too.)
Be sure that you have uploaded all the extra folders and files created by FP, (mostly starting with vti). If you left some out it could be the reason why your forms aren't working.
Most hosting services offer some cgi scripts that can be used by anyone on the server. A script for forms and one for counters are the most common ones and your hosting services may have them for you to use. Cgi scripts can be tricky to work with but they are not any harder than using FP for interactivity and they more often do what they are supposed to do. Also once you are used to working with them you have a whole world of scripts available to you that you will know how to use, as opposed to spending the same amount of time trying to get FP interactivity to work right and ending up only having learned how to use FP's very limited offering of interactivity.
Ask your server administrator (or take a look around their site) and see if they have a forms script for your use. Generally you only need to add a couple of lines of code to make your forms work this way, and there is no additional "form handler" to configure as there is in FP.
If your host does not have scripts, (mine doesn't), do a search for SCRIPTS. You'll get a lot of sites that will make a custom script for $25 - $50. If you don't want to pay for a script do your search for FREE SCRIPTS. You'll find a lot of sites for that too.
I wrestled with Front Page forms for a few weeks, and then struggled with a free one that I couldn't get to work. I wound up with a $50. custom script that works great.
Don't avoid paying for a script because you think you can do it cheaper. Your time is worth much more than that. I was also able to take the script I purchased, and alter it to make two variations that work great.