Double Slashes and Duplicate Content Pages

GOOGLE - I have posted this message several times hoping to get some
answer. I've also written support and posted this on several other
Google blogs.

We started using Sitemaps this past spring. About that time, we
started seeing duplicate entries for virtually all of our website pages
in the Google index with "double slashes" in the URLs, each entry with
a unique cache and PR. For each page that we found, we experienced a
significant drop in keyword SERPs in October, presumably due to a
"duplicate content" filter or penalty relating to Jagger.

PLEASE tell us how to remove these "double slash" entries from the
Google index. They don't show up in our logs so we can't track any
external (or internal reference). We do not have any internal
references to these pages using a "double slash". Doing 301 redirects
seems like an incredible task considering the number of pages we have
in our website.

Google Sitemap Errors is telling us that non existant pages are being
externally referenced in our site using 2, 3, 4, and sometimes 5
slashes, as if someone or some bot is fishing.