XP commands don't work on Vista - Paul Sala

I used to have to reboot my PC once and awhile to reset my DSL connection.
Then I made a bat file to reset the connection to avoid rebooting. Here are
the commands that are in that bat file:
net stop "dns client"
net start "dns client"
ipconfig /release
ipconfig /renew

This works fine on XP, but it fails on Vista. Here is what I see when it
runs on Vista as a user that has admin rights:

c:\net stop "dns client"
System error 5 has occurred.
Access is denied.

c:\net start "dns client"
System error 5 has occurred.
Access is denied.

c:\ipconfig /release
The requested operation requires elevation.

c:\ipconfig /renew
No operation can be performed on Local Area Connection while it has its
media disconnected.

Any ideas on how to get this to work on Vista?

Thanks!