Just wanted to contribute my experiences with this issue...
The issue: SharePort behaves correctly in all ways except when trying to connect (manually or automatically) to a device. It tries to connect, and after some time, the dialog box disappears and the device still says it's "available" (as opposed to being successfully "connected"). Otherwise, the status displayed of all USB devices work fine.
Routers experiencing this problem:
Mine:
DIR-655, HW A2, FW 1.31NA
USB device connected:
-Lexmark E321 monochrome laser printer
Computers connected:
-Desktop (wired connection) running Vista Enterprise 32bit SP2
-Laptop (wireless connection) running Vista Home Premium 32bit SP2
Friend's:
DIR-655, HW A4, FW 1.31NA (and also 1.32NA after updating)
USB devices connected:
-Samsung ML-2010 monochrome laser printer
-Memorex USB keyboard
-WD "Dual Option" external hard drive
Computers connected:
-Laptop (mine, same as above) connected with wireless
-Friend's laptop (wireless connection) running Vista Home Premium 32bit SP2
(SharePort version 1.1.0 R1 on all computers described)
In all these cases, I have found that the most reliable solution is power-cycling the router. It also seems that the reboot is not effective unless left off for long enough (15-30s). When having the issue, power cycling the USB device does not work reliably. Generally, the issue returns within a few hours, although sometimes it continues working for a longer period of time.
So, from my point of view, the issue has occurred on every router and ever computer I've tried. I've also been having this issue for months and this is the first time I've posted about it--so I wouldn't be surprised if there are a lot more people out there that are having similar experiences. It's unfortunate that D-Link hasn't been able to reproduce this problem--so keep testing different routers! It's a really frustrating issue and I'm looking forward to the day it's resolved.