This is not a valid URL. Please correct it and resubmit

Hi Guys,
Having problems with google sitemap.
Its pointing out that i seem to have:

This is not a valid URL. Please correct it and resubmit :- pointing at image / cache.

I've cleared all caches and it seems to be still saying that theres errors in the cache?

Any ideas? many thanks

It is missing the http.…. part of the URL

For a better Sitemap extension, try the one in my signature below