can't unlock MacBook Air 13 from iCloud remote lock

I remote locked my daughters 13 "Macbook Air using the iCloud lock function. It asks you to enter a 4 digit code. When the MacBook reboots it comes to a screen saying computer is disabled for 60 minutes. After the 60 minutes there is no place to enter the 4 digit code i entered when i remote locked it from the find my iPhone app on the iPhone. . the text on the screen on the macbook shows the "bring it down now" that i typed when i locked it.

i have tried to enter the 4 characters but there is no dialog to enter them??

I have tried a PRAM reset which shows a b&w picture of a lock after reboot on black screen then i enter the 4 digits from when i remote locked and it then goes to the grey OS X lock screen with the apple logo and no way to enter a code and the your computer is disables for 60 minutes again?

Please help!