What steps will reproduce the problem?
1. get a google ical feed like 
var url =
"http://www.google.com/calendar/ical/2v908cv63cc8je4vqsvp07bomk%40group.calendar.google.com/public/basic.ics";

var proxyUrl = gadgets.io.getProxyUrl(url);

What is the expected output? 
a file

What do you see instead?
no file

i have manually tried to unescape the url in several ways, with no luck in
pulling the file.

i suspect that the file may be too large or your proxy is timing out.

a final option is that google is rejecting your proxy for some reason.

argh this would be easier for us if google had crossdomain.xml enabled