I got the message from Google Base that the file created by Zen Cart has errors. This one is pretty important:
"We noticed that your bulk upload includes attribute names which were part of our old Froogle product feed format. For example, you've included "product_url" as an attribute name, although this attribute is named "link" in the Google Base format."
So I don't think that the Zen Cart contribution is going to work for the Google Base format.
On another note, I have a problem that is quite unique and haven't been able to solve it looking at configuration files. My Froogle output give the IP rather than the web address, so the file is also rejected as it doesn't match the address registered at Google Base. Any ideas on how to resolve this?
https://www.characterdriven.com
Character Driven Media
https://www.narnia-productions.com
Stage, Screen and Event Services and Supplies