I am having the same problem with my DGL-4500. SharePort Ver 1.1.0 R1 and Firmware 1.20NA, 2009/04/27.
The SharePort with printing capabilities was the reason I chose D-link over Linksys. It appears that I should have gone with Linksys. After spending an hour and fifteen minute talking to a tech rep in India, who wasn't even aware there was a North American version of the software, I hung up without learning a thing.
I am also having problems connecting to USB devices plugged into the router. The devices are seen in the SharePort utility, but not accessible to any of my computers. I have to reboot the router in order to connect to USB device.
After reviewing quite a few of the posts in this forum, I have come to the conclusion that if someone from D-Link actually reads any of the posts, they very rarely respond. The forum appears to be a self help and rant venting vehicle designed to keep the users occupied while D-Link does nothing.