[chryuop]

Duh...potential form, how stupid not to think about it.

The form ーておく as far as I know means doing something in preparation for a future happening. An example that comes to my mind now can be 親を電話しておいた. If for example we are talking about going a pay a visit to my parents I can use that phrase to say I already called them, a phone call made to get ready things for our future trip. I guess in this case it has the meaning of missing an important personal experience....we will have to wait for the answers LOL
I really don't think it has a real translation in English.