Mandrake (9.1 and up) and Red Hat (8.0) appear to prevent gcc2.96 compiled modules from loading with the newer gcc3.x compiled kernels, even with insmod -f (ie. force module to load). However, Slackware 9.0 and Knoppix 3.2 do not.
This is all because the HomePNA 2.0 module is proprietary, and Broadcom is not going to open source it. We're lucky they even released this driver; I waited two years before I could try Linux because of this issue (I can't run cat5 through my condo). Now that 802.11b is so cheap and available, I think that there will be no incentive for further hpna2 drivers from Broadcom.
Theoretically, you could alter Mandrake to accept the hpna2 module with a force insmod, but unless you are a kernel-hacker level programmer, why bother? If running cat5 through your house is not an option, then try wireless. The cheapest alternative, however, is to simply switch distros; that's what having a broad range of choices is all about!