I had trouble trying to start this post of.
This looks like the first site i ever made, if this is your first site then its a good first attempt. To me its abit pain need abit more "wow factor" splash some color around, maybe change the color of the example pages for your script to a lighter blue, I didnt know it was there till I accidently clicked on it.
The link on the right hand side under the About section dont work for me ("http://namepros.com/member.php?u=7163" link ) as i have to register to namepros.com which i dont want to do if i wanted to buy a script as its to much work, i would go else where.
The support page has 2 colums in the center table, when i read it, i got confused as it didnt make sence untill i saw them colums, best to make that 1 main colum or keep 2 and have the contact info on the3 left and contact name/number on right.
Downloads page, if you get about 30 scripts and the user wants to download one he will have to scroll through the list to find his script which with 30 could be a pain to find. Instead of that maybe have a login page for the user and have only what he has payed for to download, would save the need for popup problems users have.
Scripts page, aint bad however there could be a few enhancments u could do, maybe a users rating on the script 1-5 mark, buy button, download button (only shows if they have purchased script) version number of the script how many times its been downloaded. and i see you have update fixes on the script, how about clicking the script name and it will show the script in a tabbular format with details, sepec's, recent fixes, user feedback.
I think thats about it.