How to do dynamic SQL in PB

To create a dynamic SQL statement in PB i did this:

SQLTEST = "select id,name  from ss_test where id = @i;";

DECLARE cursor_base DYNAMIC CURSOR FOR SQLSA;

PREPARE SQLSA FROM :SQLTEST;

OPEN DYNAMIC cursor_base USING :i;

FETCH cursor_base INTO :i2,:test2;

however i am getting the error "Mismatch between prepared number of substitution variables and execute parameters".. Which i don't understand? This same SQL runs on the database and the i is a int value just like in the database? What am i doing wrong?

I wanted to be able to do bind variables with the SQL.