I have exactly the same problem. Try this:
(1) Unplug your router from the power source
(2) Unplug your USB printer cable from your router
(3) Plug in your router and wait until it is up and running
(4) Plug in your printer to the USB port on the router
The USB light should light up and the printer should appear in Shareport
Alternate
(1) Unplug your printer cable from your router
(2) Press the reset button (do not hold, just press)
(3) When the router has re-booted plug in the printer cable to the router the USB light will come on and the printer will appear in shareport
There appears to be an error when the printer is plugged in on boot up, it disconnects the printer in an incorrect way (similar to unplugging a USB cable from your computer without unloading it first)
No idea if its the Shareport software or the router firmware? I did reinstall the firmware didn't cure it.
DLINK needs to fix this problem. I took my original router back, but the replacement is exactly the same. I also tested my friends (he doesn't use Shareport so didn't realize the problem) his does it too. I always unplug my printer when I switch off and plug it in after the router boots up, I don't have a problem after that, both my wife and I can print from our respective computers no problem.
My firmware 2.02NA Hardware: B1
If you use the 5Ghz wireless this has a problem too sometimes it works other times it doesn't (mine does it so does my friends). I always switch my router off after I'm done (ECO friendly), sometimes I have to switch the router off 3 or 4 times before the 5Ghz works.
Hope this helps.