diff -up cups-1.4.7/backend/snmp-supplies.c.str3875 cups-1.4.7/backend/snmp-supplies.c
--- cups-1.4.7/backend/snmp-supplies.c.str3875	2011-07-07 16:44:41.000000000 +0200
+++ cups-1.4.7/backend/snmp-supplies.c	2011-07-07 16:48:19.201008765 +0200
@@ -259,7 +259,10 @@ backendSNMPSupplies(
       if (quirks & QUIRK_CAPACITY)
         supplies[i].max_capacity = 100;
 
-      percent = 100 * supplies[i].level / supplies[i].max_capacity;
+      if (supplies[i].max_capacity > 0)
+	percent = 100 * supplies[i].level / supplies[i].max_capacity;
+      else
+        percent = 50;
 
       if (percent <= 10)
       {