diff --git a/.travis.yml b/.travis.yml
index e906f4f26..cd6333dbb 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -15,8 +15,8 @@ deploy:
     api_key:
       secure: DNq1wbqLPHVpJPDx9O89HZM+RJB6v2R7/wk8pok7Z8NT72kUWdvbqcThGhczPO4sZ8cUTJ3ergTCE8hs9mynlR/lX6932U4fj4+uICQL9+G+deBB/t2SNyTBllkE64WrJ9BKmQvIk/Chh7ZJOM0Fro3p2BIq3JsVnfYg1tZ3U5o=
     file:
-      - package/chevrotain-binaries-0.5.9.zip
-      - package/chevrotain-binaries-0.5.9.tar.gz
+      - package/chevrotain-binaries-0.5.10.zip
+      - package/chevrotain-binaries-0.5.10.tar.gz
     on:
       tags : true
       all_branches: true
diff --git a/bower.json b/bower.json
index 687e11d9d..2317b532c 100644
--- a/bower.json
+++ b/bower.json
@@ -1,6 +1,6 @@
 {
   "name": "chevrotain",
-  "version": "0.5.9",
+  "version": "0.5.10",
   "description": "Chevrotain is a high performance fault Tolerant Javascript parsing DSL for building recursive decent parsers",
   "main": "release/chevrotain.js",
   "dependencies": {
diff --git a/package.json b/package.json
index 4b521372d..ffeff5aa0 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "chevrotain",
-  "version": "0.5.9",
+  "version": "0.5.10",
   "description": "Chevrotain is a high performance fault Tolerant Javascript parsing DSL for building recursive decent parsers",
   "keywords": [
     "parser",
diff --git a/release/chevrotain.d.ts b/release/chevrotain.d.ts
index 294b08ca0..964cd8dc3 100644
--- a/release/chevrotain.d.ts
+++ b/release/chevrotain.d.ts
@@ -1,4 +1,4 @@
-/*! chevrotain - v0.5.9 - 2015-12-12 */
+/*! chevrotain - v0.5.10 - 2015-12-20 */
 declare module chevrotain {
     module lang {
         class HashTable<V>{}
diff --git a/release/chevrotain.js b/release/chevrotain.js
index 8ed9102db..6d648b0aa 100644
--- a/release/chevrotain.js
+++ b/release/chevrotain.js
@@ -15,7 +15,7 @@
   }
 }(this, function (_) {
 
-/*! chevrotain - v0.5.9 - 2015-12-12 */
+/*! chevrotain - v0.5.10 - 2015-12-20 */
 var chevrotain;
 (function (chevrotain) {
     var lang;
@@ -2276,11 +2276,11 @@ var chevrotain;
                     if (_.isEmpty(chevrotain.first.first(currAlternative))) {
                         return {
                             message: ("Ambiguous empty alternative: <" + (currAltIdx + 1) + ">") +
-                                (" in <OR" + currOr.occurrence + "> inside <" + topLevelRule.name + "> Rule.\n") +
-                                "Only the last alternative is may be an empty alternative.",
+                                (" in <OR" + currOr.occurrenceInParent + "> inside <" + topLevelRule.name + "> Rule.\n") +
+                                "Only the last alternative may be an empty alternative.",
                             type: chevrotain.ParserDefinitionErrorType.NONE_LAST_EMPTY_ALT,
                             ruleName: topLevelRule.name,
-                            occurrence: currOr.occurrence,
+                            occurrence: currOr.occurrenceInParent,
                             alternative: currAltIdx + 1
                         };
                     }
@@ -3723,7 +3723,7 @@ var API = {};
 /* istanbul ignore next */
 if (!testMode) {
     // semantic version
-    API.VERSION = "0.5.9";
+    API.VERSION = "0.5.10";
     // runtime API
     API.Parser = chevrotain.Parser;
     API.Lexer = chevrotain.Lexer;
diff --git a/src/api.ts b/src/api.ts
index 3f11a8923..24b580404 100644
--- a/src/api.ts
+++ b/src/api.ts
@@ -12,7 +12,7 @@ let API:any = {}
 /* istanbul ignore next */
 if (!testMode) {
     // semantic version
-    API.VERSION = "0.5.9";
+    API.VERSION = "0.5.10";
 
     // runtime API
     API.Parser = chevrotain.Parser