404 error on some external links

Okay, I’ve tried to figure this out myself, but to no avail.

I’ve noticed that some of my external links are returning 404 errors. Specifically, what is happening is that the page address is appearing followed by the correct intended link. So, for instance, at the bottom of this page – http://www.theislandreview.com/fortarmistead – is a link that ought to go to http://www.travinsystems.com but instead goes to http://www.theislandreview.com/fortarmistead/www.travinsystems.com.

There is another on my most recent post: http://www.theislandreview.com/bewitchedsea/

I’ve tried deleting the links and inserting them again but it doesn’t help.

This is not a problem across the whole site. I searched Crawl Errors with Webmaster Tools, which shows about ten of them. But obviously that’s ten too many. I can’t see any particular connection between the pages where the links work and those where they don’t. Can anyone please enlighten me as to what’s going wrong?

Thanks