Access denied for administrator

Hi! i burnt some files in a DVD_RW. I didn't notice these files which were stored in the DVDRW are read-only. Now, I want to delete/modify some files so I go to file properties and untick the read-only box in the file. As soon as I click apply, it says I gotta have admin right to change file properties. I thought I just enter my admin password and it will do. But as I click continue (not even reaching a box prompting for password), it says access denied.
Well, I'm the administrator of this computer and these files are just recently burnt in the same computer. What would possibly be the problem? Can anyone please help?

Welcome

You must be sure that you have ownvershp, once that is established you must give yourself permission.

Sharing and Permissions - Windows 7 Forums
http://www.vistax64.com/tutorials/67717-take-ownership-file.html
For both Vista and Seven