YES. I have been going crazy trying to figure this out. I thought it was something I did, and coincidentally I got Vonage the same day I upgraded firmware from 1.2x to 1.32NA (never considered that DLINK would hose me like this). So I've been getting furious with Vonage people and their little router. I almost even cancelled the service! Then I just put the vonage router in one of the ports on my cable modem and my DLINK on another port. This works like a champ -- well, aside from the fact that my DLINK drops off the face of the internet every 6-8 hours...
The strange thing is that if I pull the plug on the DIR-655 before going to work at 11am or so, it seems to work fine all day long. I am constantly logged in and using my server from work (checking IMAP mail, ssh, etc.). But no doubt I will loose connection sometime during the night. I set up an account with http://www.pingdom.com to monitor my server and at least know when I'm hosed.
The other thing I did is write a script on my server that tries every 15 minutes to ping various IPs (not even trying DNS as if an IP can't resolve, DNS won't either).
I've posted the live log here: http://75.147.180.77/ping.log
And the bash script I used can be found as "Ping Test" here: http://daevid.com/content/examples/snippets.php
WTF. How can they break this so horribly? It's a router -- it's like what DLINK does! I could care less about 90% of the crap in the web interface aside from port forwarding. Before this upgrade, this thing ran solid and I NEVER had to reboot it even one time for months.