SITE REVIEW: www.BlackBoxForms.com

Hello
I am looking for some constructive feedback regarding my new website/webapplication: http://www.BlackBoxForms.com . It basically allows people to design their own HTML forms online. I am mostly interested in how helpful is my system in accomplishing this goal. My target audience is people somewhat familiar with CSS and HTML, not newbies.
Thank you in advance.

First off I think that the "System Message" is out of place. I don't know if you're trying to make it stand out but it appears to conceal a text box or something (at least in FF). The general layout of the site is also clean and uniform, but there seems to be too much text of the same size - and that can be overwhelming at first glance.

Try and break up your text with some larger headlines, etc. to make certain sections stand out and break up the larger sections of uniform text.

Yeah, the "System Message" shouldn't appear at all on Firefox. I fixed that.
How easy is it to design your own HTML form when you click on "Online Demo" ?

I would tell you but it won't let me on FireFox. You should really fix that.

Sorry but some things I am doing are either impossible or very time-consuming to code for Firefox (for instance: real-time layout changes).

That is just plain wrong. More and more users are switching to FireFox and other web browsers. If designing to cater to all users is "very time-consuming" then you should get out of the web design business. Considering 100,771,285 people have downloaded FF, you should consider spending the time to fix your site.

i wouldnt say im at all any good with CSS & HTML, but this site just makes me totally confused, and is very boring. you need to add more colours

Simply and usability. Congratulations!

I think you should create an ad-supported free version. Use Claxon CPM ads and Bidvertiser CPC ads, as I've learned their great for smaller sites.