after doing a search, and clicking on one of the matched criteria links, I find that I cannot hit the back button to return to that matched list. It gives me a "this webpage has expired" error every time and I've tested it on multiple machines.
I use Firefox, and I've never had that problem. What browser are you using?
I think it's probably due to your browser just telling you it wants to load the page again. Firefox (as far as I can tell) just uses it's internal cache.
I use IE7 at work and FF at home. Again - no problems. The only difference is that by default IE refreshes the page whereas FF uses its internal cache, as Yayyak says.
The search result page is the result of the form data you sent to the webserver. The warning is telling you that, to re-display the result page, it would have to send that form data (your search parameters) again. Can't be helped from our side.
Every good solution is obvious once you've found it.
