diff --git a/toinst b/toinst
index 701d40a..f078bc3 100755
--- a/toinst
+++ b/toinst
@@ -360,7 +360,7 @@ debian:*)
     ;;
 runs:*)
     v="${TOMCAT_PROFILE#runs:tomcat}"
-    if [ -z "$CATALINA_BASE" -a "$v" != "$TOMCAT_PROFILE" ]; then
+    if [ -z "$CATALINA_BASE" -a -n "$v" -a "$v" != "$TOMCAT_PROFILE" ]; then
         array_lsdirs ts /opt "apache-tomcat-$v*"
         CATALINA_BASE="${ts[0]}"
     fi