The machines on our nework running XP can access the embedded webpage for the printer.
We don't use proxy settings at all, not sure what you mean.
You mentioned on your post the Operating system version. Does this mean that other OS such as XP or any other are able to connect to the printer via HTTP?
Some steps to try could be:
I've got a Dell Precision T3500 running Win 7 64 bit OS.
My coworker has a Optiplex 755 running Win 7 32 bit OS.
We're running a MS Server 2003 network. (most other user's machines are still running XP SP3).
Neither one of us can connect to our Xerox Workcenter 5135 through IE 8/Firefox and the machine's IP address.
We type the IP address in IE8 or Firefox and the page times out.
I've also had messages along the lines of "Printer Status not available" after I print a document.
Any help would be greatly appreciated.