All CMS Builder Links suddenly return Error 403 - Forbidden

An unusual and potentially very damaging (Google links) problem has cropped up on my site and I can find no explanation for it. Essentially I've been using CMSB 2.09 for awhile, it's been perfectly happy doing its thing and I've not made any changes, yet at some point within the last 12 or 24 hours all of the links to my product detail pages have stopped working and throw out "Error 403 - Forbidden" messages.

After running some tests I could find no change to either the database or settings file, or anything, that would account for this. So I did some more digging and found what was trigging the problem but not how to resolve it and make my old links work again.

To demonstrated I created a default detail viewer file, which allows you to jot in any product number of your choosing (I use 12 as an example).

http://www.ispreview.co.uk/isp_list/ISP_Detail.php?12

This works fine, but in my public system I auto-generate an SEO friendly URL by doing things like this:

<a href="ISP_Detail.php?<?php echo preg_replace("/[ ]/", "-", $record['title']); ?>-<?php echo $record['num'] ?>" class="italhead">

As a result the above URL would become this, which worked fine until this morning..

http://www.ispreview.co.uk/isp_list/ISP_Detail.php?A-Well-Connected-12

Now I figured out that if I changed all the minus-hypens to underscores (from "-" to "_") then that resolved it but this breaks all my links in Google and is a big problem. I also tried to solve this by using the hypen-minus character code (-) instead of the character itself but the same problem occurs. Anybody have any ideas? For now I'll have to go in and adjust tons of URL calls as a temporary fix but that's going to mess up google big time and my backlinks :(!