Didn’t transfer previous PS3 account’s saved data to new account before deleting it. Is there any way to get that data back?

I created a new user account, but I did not transfer the saved data to the new account before deleting the original. Due to this machine being used before I purchased it, the account was one the original owner created. I don't know how to get back into the original account. I can still see the data saved in the “Saved Data Utility,” but when I try to copy it to my portable hard disk, it says I'm unable to transfer the files.

Is there any way to get that data back?

Some games (like Demon's Souls - I remember this game from my own experience) do not allow to copy saves. Some saved games are strictly connected with the account you played them on, so you will not have the possibility to copy them, or even make some backup on a device other than the hard drive of the console which you played on.