I got some of the DLCs ( bonfires of vanities, etc ) and installed them in one profile, now I can't access them in another profile that I had. What should I do?
Usually, if everything is on the same PS3, it should not have any problem, even if it's on two different profiles. I do not own Assassins Creed, but for many other games, I have no problem between profiles.
If you really have a problem, you should maybe think about re-download the DLC.
- search for saved position by other people
- call the support or mail Ubisoft
There links might help: