Change this section to:

```objj
var value = [self numberFromString:aString],
    error = @"";
	  	
if (!isFinite(value))
    error = @"Value is not a number";
else if (_minimum !== nil && value < _minimum)
    error = @"Value is less than the minimum allowed value";
else if (_maximum !== nil && value > _maximum)
    error = @"Value is greater than the maximum allowed value";

AT_DEREF(anObject, value);

if (error)
    AT_DEREF(anError, error);
```