Here are 2 annoying bugs that have been present in Acrobat X on the Mac since it's release. They were not repaired in the current update.
1. Open Acrobat and then open any document. Try to delete a single page. It fails. You have to do this TWICE.
2. If you open a PDF that has multiple bookmarks and try to delete several bookmarks at once, the program will crash immediately. I have to use a Windows version of Acrobat to do these multiple delete.
Mac:
http://www.adobe.com/support/downloads/detail.jsp?ftpID=5236
Also, I've seen the delete page issue resolved by un-installing Acrobat and installing it under a new user account. I haven't had the issue of deleting multiple bookmarks at all, which leads me to believe there might be an issue with your installation.
Kelly McCathran
Adobe Community Expert
Certified Technical Trainer+