[plt-scheme] A bug of srpersist?

I write the following code:

(require (lib "srpersist.ss" "srpersist"))

(define henv (alloc-env))
(define hdbc (alloc-connect henv))

(connect hdbc "system" "" "")

(let ((hstmt (alloc-stmt hdbc)))
  (prepare hstmt "USE system")
  (sql-execute hstmt))

(define (q1)
  (define id-buffer (make-buffer 'sql-c-slong))
  (define name-buffer (make-buffer '(sql-c-char 20)))
  (define tele-buffer (make-buffer '(sql-c-char 20)))
  (define add-buffer (make-buffer '(sql-c-char 20)))
  (define time-buffer (make-buffer 'sql-c-timestamp))
  (define state-buffer (make-buffer '(sql-c-char 10)))
  (define id-indicator (make-indicator))
  (define name-indicator (make-indicator))
  (define tele-indicator (make-indicator))
  (define add-indicator (make-indicator))
  (define time-indicator (make-indicator))
  (define state-indicator (make-indicator))
  (define hstmt (alloc-stmt hdbc))
  (define al '())
  (prepare hstmt "select id, name, tele, address, time1, state from bx;")
  (sql-execute hstmt)
  (bind-col hstmt 1 id-buffer id-indicator)
  (bind-col hstmt 2 name-buffer name-indicator)
  (bind-col hstmt 3 tele-buffer tele-indicator)
  (bind-col hstmt 4 add-buffer add-indicator)
  (bind-col hstmt 5 time-buffer time-indicator)
  (bind-col hstmt 6 state-buffer state-indicator)
  (with-handlers
      ([(lambda (exn) (exn-no-data? exn))
        (lambda (exn) (void))])
    (let loop ()

      (newline)
      (display id-buffer)     ;first display

      (fetch hstmt)

      (newline)
      (display id-buffer)     ;second display

      (set! al (cons (list (car (read-buffer id-buffer))
                           (car (read-buffer name-buffer))
                           (car (read-buffer tele-buffer))
                           (car (read-buffer add-buffer))
                           (let ((time1 (car (read-buffer time-buffer))))
                             (string-append (number->string (sql-timestamp-year time1))
                                            "-"
                                            (number->string (sql-timestamp-month time1))
                                            "-"
                                            (number->string (sql-timestamp-day time1))
                                            " "
                                            (number->string (sql-timestamp-hour time1))
                                            ":"
                                            (number->string (sql-timestamp-minute time1))))
                           (car (read-buffer state-buffer)))
                     al))
      (loop)))
  al)

(q1)


When running(Windows XP + DrScheme 206p1 + ODBC), the first display 
displays "#<sql-buffer>" and the second displays "1277974". 

What's wrong? 


=========================================

>Hi all,
>
>When writing something with srpersist, I meet the following problem:
>
>First I wrote the some code like the p1.scm. When it runs, a error occured at line 
>31, the "(read-buffer id-buffer)". The error messege is always "read-buffer: 
>expects argument of type <<sql-buffer>>; given 1277974 " . 
>
>I try to debug and rewrite the code into the p2.scm. But this time it works and 
>give the desired output! 
>
>I can't find any reason why these two codes should behave differently. The 
>circumstance is same and the ODBC and DBMS works well. What's wrong with the 
>p1.scm? 
>
>Zhu Chongkai
>