OK, after a lot of search I found the answer to a strange error in iWeb which occurs after you have selected 'comments on' and published your site to a ftp server. the error is something like this at the end of your pages: ('formatConversion[formatKey]') the problem was not in iWeb self, but in my calendar, where I changed the way I want the date to be shown. So the solution is this: change the date shown in the calendar to the default one. Republish your site again and Voila!
MacBook Pro 17", Mac OS X (10.6.2), music teacher and business analist