Scheme’s “expected a procedure that can be applied to arguments”

There are some unnecessary parenthesis, don’t do this:

((if (qweqwe n) (printtofile n) #f))

Try this instead:

(if (qweqwe n) (printtofile n) #f)

Also in here:

(define (qweqwe n)
  ((cond [(< n 10) #t]
         [(>= (lastnum n) (pochtilastnum n)) (qweqwe (quotient n 10))]
         [else #f])))

It should be:

(define (qweqwe n)
  (cond [(< n 10) #t]
        [(>= (lastnum n) (pochtilastnum n)) (qweqwe (quotient n 10))]
        [else #f]))

In both cases the problem was that if you surround with () an expression, it means that you’re trying to invoke a procedure. And given that the result of the if and cond expressions above don’t return a procedure, an error occurs. Also, bothbegins in your original code are unnecessary, a cond has an implicit begin after each condition, same thing for the body of a procedure definition.