Can't completely delete app?

So I was having trouble viewing a few videos, and I dl'ed Windows Media Player for Mac (flip4mac wasn't working, either...), and that didn't work. So I'm trying to delete Media Player (appzapper sent it all to the trash bin), but whenever I try to empty Trash I get messages saying, "________ is locked and can't be removed".

Any idea how to "unlock" something so it can be trashed?

Thanks in advance.

 

Thanks for the tip. Everything worked well, except I had to hold down "ctrl" to bring up the context menu.