There are a number of threads in regard to QuickVPN and issues with Windows 7 64-bit. However, most of them appear to be older (more than a month or two old), or have become inactive with no solution found. I know the latest version of QuickVPN is supposed to solve the issue, but that doesn't appear to be the case in my situation. Example threads:
I have a couple of clients on WinXP Pro successfully using QuickVPN to connect to our WRVS4400N. However, one client has Windows 7 64-bit. I've installed the latest version of QuickVPN (QVPN_UTL_18.104.22.168), and uninstalled Norton Internet Security (resetting the Windows Firewall to defaults). However, it still fails to connect, giving me a "Remote gateway is not responding." dialog.