12 keys keypad, library error when uploading!!

lookslikeruck:
I discover that I can get the numbers missing by combining two or more keys (one that works, one that's not).
For example:

Output - Key pressed
1 - 1
2 - (2 + 5) or (6 + 3)
3 - 3
4 - (4 + 5) or (0 + *) or (8 + 7)
5 - 5
6 - (6 + 8 ) or (0 + #) or (8 + 9)
7 - 7
8 - (6 + 9)
9 - 9

0 - (some combination I can't find out...)

-

This was the keypad I bought.
http://www.ptrobotics.com/product.php?id_product=426

you might want to do as suggested and use a multimeter to map out the pins (shows how in the tutorial)
i mapped mine out and this was the combination i got although the keypad is. Not all keypads that seem to be the same wiring are the same wiring

123
456
789
C0E

const byte rows = 4; //four rows
const byte cols = 3; //three columns
char keys[rows][cols] = {
  {'1','4','7'},
  {'2','5','8'},
  {'3','6','9'},
  {'C','0','E'}
};