Hi! Sorry to hear about this problem. We've heard from several visitors with Mac-related issues. What version of OS X do you have? What browser are you using?
Here's something to try:
1. Go to your MyPage
2. Click on the "Bookmarks" link in the menu at left
3. Notice the checkboxes to the right of each bookmark
4. Click on the checkbox for each bookmark you wish to delete*
5. Find the menu under the list of bookmarks. Select 'Delete' and press the 'go' button.
*Or, to select all your displayed bookmarks at once, click on the checkbox in the gray menu area at the top of your bookmarks. This should check them all at once. Then continue to step 5.
Let me know if this helped!