Well there's a happy ending to this messy problem - to avoid the long-winded process of compiling the correct modules for Luit's 2.4.22-xfs kernel, I took some drastic action.
I upgraded Luit's kernel to 2.4.26 in a very ugly fashion by deleting its kernel file plus modules directory, then replaced them with those from DamnSmallLinux.
I half expected boot failure or kernel panic ... but no, it all worked! And with the new kernel, the linux-wlan-ng drivers now work great!