Use this wad file:
http://www.superjer.com/files/zhlt.wad
It contains all the special textures for HL. MAKE SURE that when you compile, you do this in your CSG step:
[code:1]hlcsg -wadinclude zhlt mapname[/code:1]
Otherwise your map will not be playable by most people!
-wadinclude zhlt saves the zhlt.wad file INTO the bsp so that people do not need zhlt.wad seperately to load the map.