I believe that along with the move of the forums, the DIS web sites are offline temporarily. You might notice that even the graphics at the top of each page are not showing up either. I'm sure that they will be back on line soon and your signature image will be showing up in no time.
Even as I posted this, it looks like they are back. Please be patient. They may come and go for a little while as all the bugs from a move of this magnitude are worked out.