Accessing iphoto

I have the latest desktop iMac plus two iPhones ( wife and mine ), they are all linked via iCloud and of course if I take a pic with the iPhone it transfers automatically to all devices.

My problem today is that I cannot access iPhoto on my iMac.
when I click on the iPhoto icon on launchpad, the screen shows a small panel that says " This iPhoto library is locked, you do not have permission to make changes to it. iPhoto can try to repair the permission" and it shows two boxes beneath, one to repair and one to cancel.
If I click on the repair then a box comes up that requires my username and also my password, but they do not work, I know the password is right, as after a few attempts it gives me a hint as to what my password is.

Any help would be gratefully received.

Oh, should have said that if I enter a wrong password then the box gives a shudder to let me know that the password is wrong, so I correct it but then the screen goes back to the beginning again

I would start by doing a full backup, then run OnyX.

If that didn't fix the problem, I would launch iPhoto with the command and option keys held down and do every item on the fix list that comes up when you do that.

Thanks for a quick reply. But I am showing my ignorance here. What is OnyX ? and I obviously can see the command key but what are the option keys ? and what do I do ?
I think there must be a lot of us less informed people out there.

Perhaps you are not using a Mac keyboard? The option key is the one next to the command key, says "option" on it. Maybe they've changed them or something, but all mine say "option" and also say "alt" on them.

OnyX is a free utility mentioned constantly on this forum as a reliable and no-cost way to maintain your Mac. It can be run very occasionally to fix little problems before they become big problems. Get the version that matches your system version (ie 10.7, 10.8, 10.9).

Perhaps he is using a new Mac keyboard that doesn't say "option" on it, it says "alt"

Latest Mac keyboards both wired and wireless have "option" written on the keys with a small "alt" also written on the key.

Sorry that is incorrect,

I have Retina Macbook Pro about 9 months old, no where on the keyboard is the word "option"

I have the latest iMac and both my wired and wireless keyboards say option and alt on the key. If the rMBP does not have option written on the key, then it's something that Apple just started doing. Anyway, you know that they're one and the same. The problem is that new users might not know it.