Can't save Web pages

Hi!
When trying yo save Web pages appears the following message: "the . . . (file) could not be saved, because a file already exists with the same name as the '_files' directory. Try saving to a different location". There isn't same file in the mentioned place since it is the first time i try to download those (any) pages and even if i change the location same message continues appearing.
Can someone tell me want can i do to resolve the problem? Thanks a lot.