hey Jumpman,
I had the exact same problem as you. In another post you mentioned daylight saving time was whent he problem started happening ( I wouldnt have noticed that). So I logged into my Dlink admin page went under TOOLs ( along the top) then TIME (along the Left) and setup my DLINk so it the time was right ( it was an hour off, I used the get time from my computer button) then turned on DST so it automatically corrected for daylight savings. Now it works.
Hope that helps
I tried the same thing, but my DNS didn't want to use the correct time. It kept changing to an hour ahead. So I decided to use the NTP server. Now I have no problems. Funny how the time can create this issue.