diff --git a/main/sc/source/filter/html/htmlpars.cxx b/main/sc/source/filter/html/htmlpars.cxx
index 126c406..a7587ba 100644
--- a/main/sc/source/filter/html/htmlpars.cxx
+++ b/main/sc/source/filter/html/htmlpars.cxx
@@ -1912,17 +1912,19 @@ public:
         @param pTableMap  Pointer to the table map (is allowed to be NULL). */
     explicit            ScHTMLTableIterator( const ScHTMLTableMap* pTableMap );
 
-    inline bool         is() const { return maIter != maEnd; }
+    inline bool         is() const { return bValid && maIter != maEnd; }
     inline ScHTMLTable* operator->() { return maIter->second.get(); }
     inline ScHTMLTable& operator*() { return *maIter->second; }
     inline ScHTMLTableIterator& operator++() { ++maIter; return *this; }
 
 private:
+    bool bValid;
     ScHTMLTableMap::const_iterator maIter;
     ScHTMLTableMap::const_iterator maEnd;
 };
 
 ScHTMLTableIterator::ScHTMLTableIterator( const ScHTMLTableMap* pTableMap )
+: bValid( pTableMap != 0 )
 {
     if( pTableMap )
     {