My OS is 10.6.8 and I'm using iMovie '11
When I attempt to export my project in any format I get the error message: The project could not be prepared for publishing because an error occurred. (Error in user parameter list)
I was having the same problem. I exported using a file name with no special characters (- / _ etc) and no spaces. It worked. You can rename the file whatever you want after the export is finished.
Retrieving data ...