Index: db.scm
==================================================================
--- db.scm
+++ db.scm
@@ -1537,21 +1537,23 @@
 (define (db:get-index-by-header header field)
   (list-index (lambda (x)(equal? x field)) header))
 
 ;; look up values in a header/data structure
 (define (db:get-value-by-header row header field)
-  (let ((len (vector-length row)))
+  (let ((len (if (vector? row)
+		 (vector-length row)
+		 0)))
     (if (or (null? header) (not row))
 	#f
 	(let loop ((hed (car header))
 		   (tal (cdr header))
 		   (n   0))
 	  (if (equal? hed field)
 	      (handle-exceptions
 	       exn
 	       (begin
-		 (debug:print 0 *default-log-port* "WARNING: attempt to read non-existant field, row="
+		 (debug:print 4 *default-log-port* "WARNING: attempt to read non-existant field, row="
 			      row " header=" header " field=" field ", exn=" exn)
 		 #f)
 	       (if (>= n len)
 		   #f
 		   (vector-ref row n)))