To install software on your Mac,
by mrmacfixit - 3/14/12 3:45 PM
software that makes changes to the system, the system requires you to authenticate yourself as an Administrator of that machine.
When you first fired up that Macbook, it asked you to supply a username and a password. If you are the only user of that machine, then you are automatically an Administrator.
If you have automatic logon enabled, then you are never asked for this password when you start up the computer, but you will almost always be asked to supply it when you attempt to install software.
The password that you are being asked for is the password your created when you created your account on that Macbook.
It is NOT Adobe that is asking for your password, it is Mac OS X that wants it.