I am having the same issue but with an Epson R320 installed on a Vista x64 machine and the Vista x86 machine also connected to the network sees it fine, but the XP Pro system on the network won't install a driver.
I have unzipped the driver (in fact they had been used before so I know they work) and installed the printer drivers on the XP machine but still won't work.
I have tried manually searching for the INF when asked by the network install but it says they are incompatible.
I thought installing "Additional Driver" on the Vista x64 machine might work but all it supports are Vista x86 and Itanium.
rajinisback: I just tried your instructions and still won't install. Thanks for trying.