I have ftp proxy configured with one access rule at the top of the list
for ftp application proxy. Allowing my subnet access and destination as
any. I can type in ftp addresses in IE6 browser and see folders and copy
files to my desktop. When I click on links to pdf's through a website
using IE, I get a 403 forbidden error. When I disable enforce access
rules, everything works.

What other access rule do I need other than allow subnet to access any
destination site. No authentication is being used either.