I'm definitely using Goldsource (HL1) engine. I accomplished the self-illuminating light textures effect by modifying my FGD to use texture lights.
ZHLT 3.4 is the final release for the Goldsource custom map compilation tools. I'm currently using the latest version of VHLT - custom ZHLT tools which are reportedly better - but I tried compiling on both ZHLT 3.4 and VHLT.
Anyway, I solved it. Thanks anyway.