You should be able to click on “Empty” next to the Bulk Mail Folder.

Open mail, click options at the upper right, Click on General preferences, and in the next section you can choose how many emails you want displayed on each page. 25 is default, you can choose up to 200. That will solve the number you can delete at one time.
For the script error, try this and see if it will work. Click Tools, Internet options, Advanced. Scroll down to the Browsing section and remove the check mark from Display a notification about every script error.
If the second method fails, you may have to uninstall and reinstall mail.

Go next to ur bulk mail and hit emtpy and it will empty all of it for u then go to trash and hit empty and it will do the same k