There is little that can be done without more complete imformation on what you're doing. "Switching back to the dark side"? Do you mean you're using an emulator on Windows? If you're doing this on a HostFS mount in VRPC, have you set up HostFS's extension mapping properly?
In Tools > Options, go to the "Hostfs Extensions" tab and add an entry for the RISC OS type "f79", mapping to extension "css".
Anyway, Drobe article comments is inappropriate for this discussion. Please post on the NetSurf users mailing list if you need support for using NetSurf.