diff --git a/member-fees.scm b/member-fees.scm
index 8f188ad..4b13126 100644
--- a/member-fees.scm
+++ b/member-fees.scm
@@ -106,24 +106,26 @@
  ;; contain the year in the first cell and 12 cells for months after
  ;; it.
  (define (member-calendar->years-table mc)
-   (let* ((fm (member-calendar-first-month mc))
-	  (lm (member-calendar-last-month mc))
-	  (fy (month-year fm))
-	  (ly (month-year lm)))
-     (let loop ((y fy)
-		(rows '()))
-       (if (> y ly)
-	   (reverse rows)
-	   (loop (add1 y)
-		 (cons (let mloop ((m 1)
-				   (row (list y)))
-			 (if (> m 12)
-			     (reverse row)
-			     (mloop (add1 m)
-				    (cons (member-calendar-entry->string
-					   (member-calendar-query mc (make-month y m)))
-					  row))))
-		       rows))))))
+   (if (null? mc)
+       '()
+       (let* ((fm (member-calendar-first-month mc))
+	      (lm (member-calendar-last-month mc))
+	      (fy (month-year fm))
+	      (ly (month-year lm)))
+	 (let loop ((y fy)
+		    (rows '()))
+	   (if (> y ly)
+	       (reverse rows)
+	       (loop (add1 y)
+		     (cons (let mloop ((m 1)
+				       (row (list y)))
+			     (if (> m 12)
+				 (reverse row)
+				 (mloop (add1 m)
+					(cons (member-calendar-entry->string
+					       (member-calendar-query mc (make-month y m)))
+					      row))))
+			   rows)))))))
 
  ;; Converts the whole calendar into a list of amounts (fees)
  (define (member-calendar->fees mc)