Okay, to check if it's a preference issue, open a new user account in System Preferences and see if you can export photos form that version of iPhoto. Of course, you'll need to import a few photos beforehand.
I was talking to one of my friends, who had recently been uploading photos onto my computer, to put onto facebook (which is like myspace for anyone who didnt know)
So he was doing that, and saw that facebook has an iPhoto plugin that lets you upload pictures directly from iPhoto. So he downloaded that... and installed it. Obviously it didnt work, because it is only for iPhoto 5.. and I have 4.
So I right clicked on iPhoto, saw its contents and removed the plug in Facebook.iPhotoExporter
Now it works.
(sorry i was putting off making a new account....... my computer is getting slow these days, and Im nearly out of space on my HD, so i was trying every other option first. But Im sure if I did that, and it worked, mad jew would have known where to look. So thanks