Bukkit

What steps will reproduce the problem?
1. Make a buy house or sell house sign.
2.
3.

What is the expected output? What do you see instead?
Expected: The buy sign should show the house class, house number and price and it should set me as owner once i right-clicked it
What really happened: Once I created the sign with [buy house] on line 1, class 1 on line 2, number 1 on line 3 and leaving an empty line 4. After clicking "create sign", it says: Error on line 2: Class must be a number. This happen despite having the class 1 in the config file and that it is a number.

What version of the product are you using?
Houses 1.7

Do you have an error log of what happened?
none

Please provide any additional information below.