Can't mark items as sold ?!

I had two items for sale which both sold within 24 hours. But Amart won't let me go in there to mark them as Sold. After I confirm that I want to mark the item as sold it just displays this error message:

The classified you requested could not be modified

It DOES let me go in there and edit the ad, so I have appended *SOLD* to the ads, but they will of course still show up in user's lists that are only looking for unsold items, so I'm still getting emails from prospective purchasers. Anyone have any idea why this is happening (didn't happen to me a couple of weeks ago when I placed an ad). :S

Ok, I finally figured this out. I use AdMuncher which is an app that strips out ads from web pages (how does anyone put up with all that crap?!?) - but for some bizarre reason, I can't mark an ad as sold when AdMuncher is active - temporarily disabling it suddenly caused marking an ad as sold to work again.

Go Figure..... ?!?