Model: WCP55AG v1.2
Operating System: Windows 98 (Note: might work with other versions of this os.)
Before downloading: Run Free Scan for Instant Driver Updates
The WPC55AG v1.2 only seems to work correctly with these drivers, a point even Linksys mention in the text files of the other versions. As to why they've failed to put this version on their website is a answer I'm still waiting on.
I hope this helps someone.