Yeah, I mean different fpc4nds and devkitARM versions. That guide refers to outdated packages, so the only way to make things working again is: (1) install the very latest devkitARM and (2) recompile fpc4nds from svn trunk. Step (1) should be trivial; step (2) is a bit more tricky. Telling long story short, there isn't a step-by-step guide about building fpc4nds on linux, but the one I wrote about building powerpc-wii on Windows is pretty much the same thing, it just needs some obvious changes. About the x64 question, I don't know, sorry, but if there is a x64->arm crosscompiler, then it should work.

By the way, I'm thinking about building some snapshots and keeping them updated, because the different release timing between fpc and devkitARM. This way, when a new devkitARM version is released, I can update these snapshots, without waiting for a new fpc release.