Problems with JS and Netscape

I wonder how many times you've seen this title here?

Here goes:

I have an ASP based site with some Java Scripts in it. There seems to be a major problem with presenting some of the pages.

The site lets users build a homepage for their cats. User provides some info and pictures and the aplication turns this into a web page.

Here's an example of a cat page. You will see there's an error in Explorer but it manages to present the page well enough. Netscape, on the other hand, does what Netscape is supposed to do - give you an error message and stop there.

http://www.thecatsite.net/one_cat.asp?cat1=3&cat=120

The main page of the site is http://www.thecatsite.net - you can also try out searching for other cat pages from there.

Please do not refer anyone to these pages yet. This is still the beta version and it's not officially launched yet. You can try out the system if you feel like it, but it's all going to be deleted before in a few days.

Any help will be greatly appreciated - only please please make it simple - I really don't know any java script to speak of. The whole site was written by someone else.

Thanks!