I'm lost...

The hpt372 open source driver/instructions are confusing. You can download the drivers/readme at http://www.highpoint-tech.com

I'm using the source (2.4.19) from ftp://ftp.us.kernel.org, and I can't find:
{DEVID_HPT34X, "HPT34X", PCI_HPT34X, NULL, ...
{DEVID_HPT366, "HPT366", PCI_HPT366, ATA66_HPT366, ...

Anyone else have a HPT372 and mandrake?

linux and raid

Try gentoo. It probably supports the HPT controller. At least, I'm going to give it a try...