I have a Dell printer connected to the USB printer port on my US Robotics
MaxG Wireless Router. I am trying to connect to it with Vista Home Premium.
I have configured the printer port on the router and can connect and print
without problems from my XP computers. The network address for the printer is
http://192.168.1.199:1631/printers/My_Printer. When I use that address in the
Add Printer wizard in Vista it does not see the printer. When I force it to
install, it will not print. When I look at the Ports tab on the printer
properties in Vista, it looks the same as it does in XP, except the Enable
Bidirectional Support box is not checked and is grayed out. The printer
shows up as Ready on the Printers list, but I get an error when I try to
print a test page.

I too am having the same problem. Its obviously connected since you can alter the printer properties but it will not print. XP was no issue. I emailed US Robotics since there is not one Vista related issue on their site. Let's see what the techies say.

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I think it is a bug in Windows http printing protocol. I have a linux http
print server and there is the same issue. No problems on XP. On Vista it
looks ok except you can't print ...

Maybe this debugging output will help someone to find a solution. This is a
point where Vista stops:
cupsdIsAuthorized: auth=AUTH_ALLOW...
cupsdProcessIPPRequest: 10 status_code=0 (successful-ok)
cupsdProcessIPPRequest: Adding fd 10 to OutputSet...
cupsdWriteClient: 10 bytes < 0
cupsdWriteClient: Removing fd 10 from OutputSet...
cupsdReadClient: 10, used=0, file=-1 state=0
cupsdReadClient: httpGets returned EOF...
cupsdCloseClient: 10
cupsdCloseClient: Error in the push function.
cupsdCloseClient: Removing fd 10 from OutputSet...
cupsdReadClient: 10, used=0, file=-1 state=0
cupsdReadClient: http error seen...
cupsdCloseClient: 10
cupsdCloseClient: Removing fd 10 from InputSet and OutputSet...
cupsdWriteClient: 9 bytes < 0
cupsdWriteClient: Removing fd 9 from OutputSet...
cupsdReadClient: 9, used=0, file=-1 state=0
cupsdReadClient: httpGets returned EOF...
cupsdCloseClient: 9
cupsdCloseClient: Error in the push function.
cupsdCloseClient: Removing fd 9 from OutputSet...
cupsdReadClient: 9, used=0, file=-1 state=0
cupsdReadClient: http error seen...
cupsdCloseClient: 9
cupsdCloseClient: Removing fd 9 from InputSet and OutputSet...