Cannot delete files fromTime Machine backup anymore?

Here is my setup. I just got a brand new MBP with Lion. I set it up the same way as my old one with an ADMIN account and a user account. The user account does not have admin rights and I sign in each time I to do major things. I felt this was a little more secure way to set it up.

Here's my problem. I have a file that I want completely removed from my system. I have deleted it and emptied the trash. Since I use time machine, I also went there and found it in my last backup but, I cannot it there now. I can no longer right-click it or use the little gear looking thingy with the drop down that gives me the options to delete all occurrences of it. I have done this many times on my old MBP with Snow Leopard, but this new one has Lion. I would just have to enter the admin name and password but I don't even get the option now. Did they change time machine in Lion so you can't delete files from Time Machine or has the process just changed? Thanks