When you unzip zoners, you will have a folder that has 4 compiling tools in it.
hlcsg.exe, hlbsp.exe, hlvis.exe and hlrad.exe
In the build programs tab (You are using Worldcraft / Hammer ??)
Use the [b]Browse[/b] button at the end of the box to link:
CSG executable box to the hlcsg.exe file in your ZHLT folder.
BSP executable box to the hlbsp.exe file in your ZHLT folder.
VIS executable box to the hlvis.exe file in your ZHLT folder.
RAD executable box to the hlrad.exe file in your ZHLT folder.