diff -p -up cups-1.3.7/scheduler/ipp.c.old cups-1.3.7/scheduler/ipp.c
--- cups-1.3.7/scheduler/ipp.c.old	2008-06-19 09:31:30.000000000 -0400
+++ cups-1.3.7/scheduler/ipp.c	2008-06-19 09:31:36.000000000 -0400
@@ -9595,6 +9595,8 @@ start_printer(cupsd_client_t  *con,	/* I
   http_status_t		status;		/* Policy status */
   cups_ptype_t		dtype;		/* Destination type (printer/class) */
   cupsd_printer_t	*printer;	/* Printer data */
+  char method[255];
+  char command[1024];
 
 
   cupsdLogMessage(CUPSD_LOG_DEBUG2, "start_printer(%p[%d], %s)", con,
@@ -9615,6 +9617,19 @@ start_printer(cupsd_client_t  *con,	/* I
     return;
   }
 
+  /*
+   * Check if backend command is present
+   */
+
+  sscanf(printer->device_uri, "%254[^:]", method);
+  snprintf(command, sizeof(command), "%s/backend/%s", ServerBin, method);
+  if(access(command, F_OK))
+  {
+    send_ipp_status(con, IPP_NOT_ACCEPTING,
+                    _("Backend is not accessible"));
+    return;
+  }
+
  /*
   * Check policy...
   */