Try changing it to:

'kfmclient openProfile webbrowsing'

in Menu Editor.

Sorry, missed the 'homepage' bit.

Once you got it running again, go to site you want to be your home page and open 'Settings' and select 'Save View Profile "webbrowsing"', and save it as default profile for web browsing, now every time you start Konqueror, it opens with your homepage.