Index: trunk/autoquest-core-tasktrees/src/main/java/de/ugoe/cs/autoquest/tasktrees/temporalrelation/utils/SimilarTasks.java
===================================================================
--- trunk/autoquest-core-tasktrees/src/main/java/de/ugoe/cs/autoquest/tasktrees/temporalrelation/utils/SimilarTasks.java	(revision 1976)
+++ trunk/autoquest-core-tasktrees/src/main/java/de/ugoe/cs/autoquest/tasktrees/temporalrelation/utils/SimilarTasks.java	(revision 1980)
@@ -899,5 +899,5 @@
                 ((IIterationInstance) instance).size() > 1)
             {
-                // iteration repeates multiple event tasks and is executed multiple times -->
+                // iteration repeats multiple event tasks and is executed multiple times -->
                 // store path
                 result.add(currentPath.subPath(0, currentPath.size())); // ensure to create a copy
@@ -948,14 +948,13 @@
         for (TaskPath leftPath : iterationsWithMultipleExecutions) {
             if (leftPath.getTask(0).equals(leftHandSide)) {
-                int[] leftIdxs = leftHandSideTraversal.getIndexesRootedBy(leftPath);
-                
                 for (TaskPath rightPath : iterationsWithMultipleExecutions) {
                     if (rightPath.getTask(0).equals(rightHandSide)) {
+                        int[] leftIdxs = leftHandSideTraversal.getIndexesRootedBy(leftPath);
                         int[] rightIdxs = rightHandSideTraversal.getIndexesRootedBy(rightPath);
                         
                         adaptIndexesBasedOnDeltas(leftIdxs, rightIdxs, patch.getDeltas());
                         
-                        if (((leftIdxs[0] < rightIdxs[0]) && (rightIdxs[0] <= leftIdxs[1])) ||
-                            ((rightIdxs[0] < leftIdxs[0]) && (leftIdxs[0] <= rightIdxs[1])))
+                        if (((leftIdxs[0] <= rightIdxs[0]) && (rightIdxs[0] <= leftIdxs[1])) ||
+                            ((rightIdxs[0] <= leftIdxs[0]) && (leftIdxs[0] <= rightIdxs[1])))
                         {
                             overlappingIterations.add(leftPath);
@@ -1239,4 +1238,8 @@
                              TaskTraversal traversal2)
     {
+        if (patch.getDeltas().size() == 0) {
+            return 0;
+        }
+        
         int diffCount = 0;
         int allCount = 0;