[amibroker] getting an error in my if statement

[lifes_student_1]

condition1 = cross(close, ma(close,20));
barsback = BarsSince(condition1 == true);
if(barsback < 6)
{...

I'm getting error 6 on barsback in if statement. condition1 is set and 
works as I've tested it elsewhere. What am I doing wrong?

(Condition in IF, WHILE, FOR statements has to be Numeric or Boolean 
type. You cannot use an array here....)