Thank you for posting.
One possible reason why Instant Web Publishing would not start is permissions. Are you currently logged in to the machine with an Admin account, especially the one that was used to install FMP?
Another possibility is a corrupt web.prefs file. Please try deleting this file and restarting the Instant Web Publishing:
/Applications/FileMaker Pro 10 Advanced/Extensions/Web Support/web.prefs
Also, what is the exact error message you receive?
Deleting the web.prefs worked! They probably got corrupted when I turned on IWP while Web Sharing was also on and the ports conflicted. This time, I set the IWP port to the Filemaker port 591 with Web Sharing off, then turned WS back on.
I was not expecting Filemaker to be writing a preference file within /Applications/ -- I would have expected it to be in /Library/Preferences/. Also, renaming the file to
com.filemaker.web.prefswould make it much easier identify in a search, than the generically named
Thanks for your help!