Your trial download link keeps sending me to another page instead of getting the file in Netscape 4.77 - this page is what I get instead of the exe:
http://www.curiouslabs.com/trade/productlist/5

Netscape 4.x does not support spaces in filenames, that is the issue because when I copy the link and remove all the spaces inserting the %20 instead, I get the file save dialog.

http://www.curiouslabs.com/products/avatarlab/Avatar%20Lab%20Trial%20Setup.exe

will work in Netscape but not what you have now

The filename with spaces link in IE5 starts the file download.