diff --git a/tomcat-uid/bin/shutdown.sh b/tomcat-uid/bin/shutdown.sh
index e454500..cd0c97d 100644
--- a/tomcat-uid/bin/shutdown.sh
+++ b/tomcat-uid/bin/shutdown.sh
@@ -19,6 +19,12 @@
 # Stop script for the CATALINA Server
 # -----------------------------------------------------------------------------
 
+# Better OS/400 detection: see Bugzilla 31132
+os400=false
+case "`uname`" in
+OS400*) os400=true;;
+esac
+
 # resolve links - $0 may be a softlink
 PRG="$0"
 
@@ -31,16 +37,24 @@
     PRG=`dirname "$PRG"`/"$link"
   fi
 done
- 
+
 PRGDIR=`dirname "$PRG"`
 EXECUTABLE=catalina.sh
 
 # Check that target executable exists
-if [ ! -x "$PRGDIR"/"$EXECUTABLE" ]; then
-  echo "Cannot find $PRGDIR/$EXECUTABLE"
-  echo "The file is absent or does not have execute permission"
-  echo "This file is needed to run this program"
-  exit 1
+if $os400; then
+  # -x will Only work on the os400 if the files are:
+  # 1. owned by the user
+  # 2. owned by the PRIMARY group of the user
+  # this will not work if the user belongs in secondary groups
+  eval
+else
+  if [ ! -x "$PRGDIR"/"$EXECUTABLE" ]; then
+    echo "Cannot find $PRGDIR/$EXECUTABLE"
+    echo "The file is absent or does not have execute permission"
+    echo "This file is needed to run this program"
+    exit 1
+  fi
 fi
 
 exec "$PRGDIR"/"$EXECUTABLE" stop "$@"