If you can't delete them with dreamweaver, try it with Bullit FTP or WS_FTP. Dreamweaver's FTP is very basic and (to my opinion) needs a makeover ;-) If you still can't delete them, than take a closer look to the security settings of the files
I assume you have a copy of your web on your computer. If so, open your web live with Front Page then delete everything, then republish using FTP. Or, create a blank web using FP, publish it to your current site telling the program to over-write the existing web, then republish using FTP. Both methods should clear out all FP referrences.