Bi-directional printing

Just installed a new network printer (a Canon for what it's worth). Set it up with my laptop and I can scan, print, fax etc. Set it up with the other laptop using exactly the same procedure; it can scan, print, fax etc. except it complains every time that it can't communicated with the printer and that I should "enable bi-directional printing" in the printer properties. Which would be great if it wasn't greyed out.

Both Vista machines though different flavours; exactly the same disc; exactly the same drivers. Checked the registry and hoy boo I've got a whole heap of extra settings in mine that are missing from the other one included tell-tales such as CnmLM_BidiSupport and CnmSLM_BiDirectionalPort. Added them in and still nada; this is just friggin' ridiculous.

I'm just wondering if I set it up as a local USB and then just change the port it'll make a difference? Pfft I've searched the interwebs and this seems to be a common problem with a myriad different solutions. I'd say it was the drivers, but I've downloaded and tried the latest set with the same result.

Oh and just to add insult to injury the Fax printer component happily shows up as bi-directional.