I just installed Splix-2.0.0 and CUPS on NetBSD/amd64 5.0.1, and I too have difficulties with a brand new Samsung ML-1640.
First of all, I had to hack on the source a bit because the debugging output claimed not to know about compression method 0; that turned out to be because for some reason in src/document.cpp, header.cupsCompression is 0. I forced it to 17 and then I got some output, but the printer didn't like it and printed an error page. See below. Otherwise, for the CUPS test page, the printer made some sounds as if it was going to print something, but then stopped and didn't. The printer test page (hold button down for a few seconds) seems to be ok.
Printer error page (layout is not exact):
INTERNAL ERROR - FALSE
POSITION: 0x11 (17)
VERSION: SPL 5.07 06-27-2006
Addendum: the output I generated manually, that the printer errored on, was ok according to the tools/decompress program: it turned it into an ok-looking PBM file.
A pity one can't edit posts, because it seems to work for me now. After confirming that a test page "printed" to a file: printer and then cat-ed to the real printer worked, I changed the URI from
, and that made it work…