Günther,
You can not use numbers for topics when using CHM files. It does not work. Please use strings. i.e:
HelpTopic("Setup") // this works fine with your CHM file
Use strings that correspond to one of the Contents entries, or a specific opic string from your CHM builder tool.
Regarding the use of lShow, what we do is to avoid the show of help if the help is already displayed. It can't be a CLASSDATA or you will be limited a just one shown help from your app, when you can have several simultaneously (not the same as "recursive", that is what lShow controls).