You did something wrong.
Was this paid code for OS X 10.8 Mountain Lion or OS X 10.7 Lion?
Yes, your Mac does NOT meet the minimum hardware requirements for OS X 10.8 Mt. Lion.
However, your Mac should be able to run OS X 10.7 Lion.
There is a very wide list of system and hardware requirements for running OS X 10.7 Lion.
The requirements are based on speeds of CPUs and NOT specific, entire Mac hardware.
You should be able to download and install this on your MacBook.
Does your MacBook have an Intel Core2Duo CPU in it?
To find out info about your system,
click on the Apple symbol in the upper left of the OS X main menu bar. A drop down menu appears.
Click About this Mac. A smaller popup window appears. This gives you basic info like what version of OS X your iMac is running, the speed of your iMac's CPU and how much RAM is installed.
Click on the button that says More Info. A larger window appears giving you a complete overview of your iMac's hardware specs.
Highlight all of this info and copy/paste all of this into another reply to this post, editing out your iMac's serial number before actually posting the reply.
I had already gave you a link to OS X 10.7 Lion.
Here it is one more time!
You should be able to download this OS X version and install this on your MacBook.
http://store.apple.com/us/product/D6106Z/A/os-x-lion