Hello everyone,
I had my DIR 655 for awhile, and most of the time, other than shareport, everything works great.
Last week, I found out D-Link released Shareport 3.0, and first few days, it doesn't work (I can connect my USB HDD every time I reboot my macbook, but after I turn off the Shareport, and restart, I kept getting Connect Failed message, unless i reboot my macbook.)
After few hours testing, here is the config i used for my router. And hope it helps.
Firmware Version :1.32NA, 2009/07/09
Firmware Version: 1.32NA
Hardware Version: A4
Product Page: DIR-655
Mac SharePort Utility 3.0 3/22/2010
OS X 10.6.3
USB HDD: Iomega 1TB Storage Device
Most of the settings are default, BUT I turn off Securespot services, turn off Multicast Streams, turn off HTTPS Server.
Give a try, and good luck.