Sorry to hear. Haven't had this one...just changed some seats yesterday. Did have a prob once due to they kinda have a different scroll-closer inside margin vs outer to see entire plane lay out. Also, found that sometimes can only see the class of service I booked. Otherwise have to go in like I'm just searching for a flight to view all seats in all classes of service. Hope things work out for you.
When I chose my seats on airberlin recently (after I had already purchased the flight), there was no seat map available. I had to call airberlin and discuss seat availability with the customer service representative while looking at a seat map on www.seatguru.com.
I finally figured out what was wrong. When I click on "view seat" and the seat map comes up, a strip comes up at the top of the page (don't know what else to call it) and at the end is what looks like a torn piece of paper. When I click on that icon, it says compatibility view, and recommends that some computers need this view and it worked! Don't know why this has started all of a sudden, but at least I know what to do now.