New DNS settings from router not pushed to all stations

After updating the static DNS settings on our Cisco WRVS4400N router, approx 1/3 of stations did not receive the new DNS settings. On the stations that did not receive the new settings,

ipconfig /all

still shows the old DNS settings.

Network has approx 15 workstations. Mix is half/half Windows 7 Home Premium / Windows 7 Professional.

There is no relationship between the Windows version and which workstations are not getting the new DNS settings. (Stations that received the new settings did so immediately, without rebooting)

There is no relationship between stations rebooting and receiving the new DNS settings.

I have tried:

• rebooting
• ipconfig /flushdns
• ipconfig /release and then /renew -- however, received message to the effect that "no adapters are in a state to respond" to those commands.

Suggestions? Ideas? Insights? Things to try?