diff --git a/collects/net/imap-unit.ss b/collects/net/imap-unit.ss
index dff1295..25f549e 100644
--- a/collects/net/imap-unit.ss
+++ b/collects/net/imap-unit.ss
@@ -318,7 +318,8 @@
 				[(!) "FLAGS.SILENT"]			    
 				[else (raise-type-error
 				       'imap-store
-				       "mode: '!, '+, or '-")])
+				       "mode: '!, '+, or '-"
+				       mode)])
 			      flags)
 		      void))))