diff --git a/db/query.cpp b/db/query.cpp
index c040bfdde61..c6b6cc5086f 100644
--- a/db/query.cpp
+++ b/db/query.cpp
@@ -288,22 +288,25 @@ namespace mongo {
         void getMods( const BSONObj &from );
         bool applyModsInPlace( const BSONObj &obj ) const;
         BSONObj createNewFromMods( const BSONObj &obj );
+
         void checkUnindexed( const set<string>& idxKeys ) const {
             for ( vector<Mod>::const_iterator i = mods_.begin(); i != mods_.end(); i++ ) {
                 // check if there is an index key that is a parent of mod
                 for( const char *dot = strchr( i->fieldName, '.' ); dot; dot = strchr( dot + 1, '.' ) )
                     if ( idxKeys.count( string( i->fieldName, dot - i->fieldName ) ) )
-                        uassert("can't $inc/$set an indexed field", false);
+                        uassert("E12010 can't $inc/$set an indexed field ", false);
                 string fullName = i->fieldName;
                 // check if there is an index key equal to mod
                 if ( idxKeys.count(fullName) )
-                    uassert("can't $inc/$set an indexed field", false);
+                    uassert("E12011 can't $inc/$set an indexed field", false);
                 // check if there is an index key that is a child of mod
                 set< string >::const_iterator j = idxKeys.upper_bound( fullName );
-                if ( j != idxKeys.end() && j->find( fullName ) == 0 )
-                    uassert("can't $inc/$set an indexed field", false);                    
+                if ( j != idxKeys.end() && j->find( fullName ) == 0 && (*j)[fullName.size()] == '.' ){
+                    uassert("E12012 can't $inc/$set an indexed field", false);                    
+                }
             }
         }
+
         unsigned size() const { return mods_.size(); }
         bool haveModForField( const char *fieldName ) const {
             // Presumably the number of mods is small, so this loop isn't too expensive.
diff --git a/jstests/update5.js b/jstests/update5.js
index 4ff9f1b9d38..d3e443565f7 100644
--- a/jstests/update5.js
+++ b/jstests/update5.js
@@ -7,6 +7,7 @@ function go( key ){
 
     function check( num , name ){
         assert.eq( 1 , t.find().count() , tojson( key ) + " count " + name );
+        printjson( t.findOne() );
         assert.eq( num , t.findOne().n , tojson( key ) +  " value " + name );
     }
     
@@ -36,5 +37,6 @@ go( { a : 5 , b : 7 } );
 go( { a : null , b : 7 } );
 
 go( { referer: 'blah' } );
-//go( { referer: 'blah', name: 'bar' } );
-//go( { date: null, referer: 'blah', name: 'bar' } );
+go( { referer: 'blah', lame: 'bar' } );
+go( { referer: 'blah', name: 'bar' } );
+go( { date: null, referer: 'blah', name: 'bar' } );