Index: trunk/MagicSoft/Mars/mfileio/MChain.cc
===================================================================
--- trunk/MagicSoft/Mars/mfileio/MChain.cc	(revision 4746)
+++ trunk/MagicSoft/Mars/mfileio/MChain.cc	(revision 4756)
@@ -18,5 +18,5 @@
 !   Author(s): Thomas Bretz, 12/2000 <mailto:tbretz@astro.uni-wuerzburg.de>
 !
-!   Copyright: MAGIC Software Development, 2000-2003
+!   Copyright: MAGIC Software Development, 2000-2004
 !
 !
@@ -24,13 +24,15 @@
 
 /////////////////////////////////////////////////////////////////////////////
-//                                                                         //
-// MChain                                                                  //
-//                                                                         //
-// Helper class for MReadTree                                              //
-//                                                                         //
+//
+// MChain
+//
+// Helper class for MReadTree
+//
 /////////////////////////////////////////////////////////////////////////////
 #include "MChain.h"
 
 ClassImp(MChain);
+
+using namespace std;
 
 Int_t MChain::LoadTree(Int_t entry)
Index: trunk/MagicSoft/Mars/mfileio/MReadTree.cc
===================================================================
--- trunk/MagicSoft/Mars/mfileio/MReadTree.cc	(revision 4746)
+++ trunk/MagicSoft/Mars/mfileio/MReadTree.cc	(revision 4756)
@@ -609,4 +609,13 @@
 
     //
+    // It seems, that TFile and TTree are not completely independant if
+    // many times the same file is openes (MReadReports) and some of
+    // the files in the chains don't have one tree. TChain::fTreeNumber
+    // is already set before LoadTree from GetFile is called and
+    // it crashes. ResetTree makes sure, that the tree number is -1
+    //
+    fChain->ResetTree();
+
+    //
     // check for files and for the tree!
     //