Why do uploaded files in Yahoo Group not display?

I am a moderator for a group and after about 12 hours after uploading a file, that file becomes unloadable. I've uploaded an HTML file and a PDF... they displayed when first uploaded, now , 12 hours later, they are 'file not found' when you click on the link. Furthermore the HTML file had some photos (linked from our yahoo group photo area.) Even when the HTML file was opening, it would only show the photos sometimes... seems like yahoo is changing the url locations of these photos after upload... Is it doing the same with the file uploads? I also have members that have reported that they get emails of new posts but cannot see the new posts when they log in... It's laughable that an internet giant like yahoo would have such basic usability problems with their groups live interface... Aren't these types of basic bugs supposed to be worked out in a test environment before pushing live? That's what most intenet companies do... Anyone else having this problem