Multiple Delete Using Checkboxes

I have created my own web mail system, and when the user has mail is automatically inserts it into a database. Now I need to be able to allow the user to delete the mail, either 1 or more at a time.

I have two select boxes, ones the option of what to do with the selected mail. Then I have another box which is only for the likes of moving mail to a different folder ( ie personal folders ).

Now When I select the mail I want to delete, then select Delete from the drop down box and then press submit, It should then loop through all the selected items and then delete them.

But when I try it doesn't delete them and doesn't provide an error, then I looked into it and used this: Code: