See if this KB article is of any assistance. It sounds as if the *bad* machines don't have something installed right....

--- PRB: HTML Help Does Not Work from VFP Application ---
http://support.microsoft.com/?scid=314296


>Hi Phil
>
>That is the issue.
>On some machines it fire but on others it does not.
>
>Mo
>
>>In the distributed app, does the chm fire when F1 is pressed?
>>
>>>I am using SET HELP To filename.CHM
>>>
>>>>How are you launching the help file from within the Fox app? If you are using a RUN command, try substituting just HELP and see if it will work.
>>>>
>>>>>Hi
>>>>>
>>>>>We have .chm help file and use the SET HELP To filename.CHM.
>>>>>
>>>>>After distribution the application, Help work on some machines and does not work on other machines. anyone have this problem?
>>>>>
>>>>>On the machines that does not works, the .CHM will work if the user double click on the .CHM file in windows explorer but not from inside the application.
>>>>>
>>>>>I am using vfp7 but it happened when used vfp6 also.
>>>>>
>>>>>Mo