Thanks, web clipper just came back this morning, so who knows, maybe a firefox glitch or maybe one of the pages caused a problem. I will get a clipper installed into another browser as that seems to be the best workaround - will probably use Internet Explorer so as not to have to install another program.
None of the other options suggested approximates the same function, of getting a complete and "live" web page with intact links into Evernote, which as far as I have used it, is the main advantage of the clipper. Doing a "save page as" into a folder is the next best thing but obviously moving stuff out of Evernote defeats the usefulness of Evernote.
Thanks for the replies!