>>>Hello,
>>>
>>>For my applications, I create a CHM compliled HTML help. I also ship the Foxhhelp8.exe (which I place in the application directory) and the foxhhelpps8.dll into common files directory.
>>>
>>>In the program, I SET HELP TO MyHelp.CHM, but HELP or F1 does not work.
>>
>>The DLL needs to be registered on target machine.
>
>Wich DLL?

The one you mention - foxhhelpps8.dll. Though, my experience with this area comes from VFP7, in VFP8 I haven't had an application which would use chm help.