Index: /fact/tools/pyscripts/pyfact/pyfact.py
===================================================================
--- /fact/tools/pyscripts/pyfact/pyfact.py	(revision 14421)
+++ /fact/tools/pyscripts/pyfact/pyfact.py	(revision 14422)
@@ -461,5 +461,5 @@
 import ctypes
 
-class SlowData( FactFits ):
+class SlowData( object ):
     """ -Fact SlowData File-
 
@@ -471,11 +471,18 @@
         * variable table column access, thus possibly increased speed while looping
     """
+    def __del__(self):
+        del self.f
+    
     def __init__(self, path):
         """ creates meta and columns dictionaries
         """
+        import os
+        
+        if not os.path.exists(path):
+            raise IOError(path+' was not found')
         self.path = path
         self.__module__ = 'pyfact'
         try:
-            FactFits.__init__(self,path)
+            self.f = FactFits(path)
         except IOError:
             print 'problem accessing data file: ', data_file_name
@@ -507,9 +514,13 @@
                 value: tuple( numerical value, string comment)
         """
+        # abbreviation
+        f = self.f
+        
         # intermediate variables for file metadata dict generation
-        keys=self.GetPy_KeyKeys()
-        values=self.GetPy_KeyValues()
-        comments=self.GetPy_KeyComments()
-        types=self.GetPy_KeyTypes()
+        
+        keys=f.GetPy_KeyKeys()
+        values=f.GetPy_KeyValues()
+        comments=f.GetPy_KeyComments()
+        types=f.GetPy_KeyTypes()
         
         if len(keys) != len(values):
@@ -555,11 +566,14 @@
                     unit - string like 'mV' or 'ADC count'
         """
+        # abbreviation
+        f = self.f
+        
         # intermediate variables for file table-metadata dict generation
-        keys=self.GetPy_ColumnKeys()
+        keys=f.GetPy_ColumnKeys()
         #offsets=self.GetPy_ColumnOffsets() #not needed on python level...
-        nums=self.GetPy_ColumnNums()
-        sizes=self.GetPy_ColumnSizes()
-        types=self.GetPy_ColumnTypes()
-        units=self.GetPy_ColumnUnits()
+        nums=f.GetPy_ColumnNums()
+        sizes=f.GetPy_ColumnSizes()
+        types=f.GetPy_ColumnTypes()
+        units=f.GetPy_ColumnUnits()
     
         # zip the values
@@ -675,5 +689,5 @@
         
         # Set the Pointer Address 
-        self.SetPtrAddress(colname, local)
+        f.SetPtrAddress(colname, local)
         self._table_cols[colname] = local
         if number_of_elements > 1:
@@ -764,4 +778,7 @@
             returns self
         """
+        # abbreviaition
+        f = self.f
+        
         # Here one might check, if looping makes any sense, and if not
         # one could stop looping or so...
@@ -771,5 +788,5 @@
         #   print 'warning: looping without any registered columns'
         if self._current_row < self.number_of_rows:
-            if self.GetNextRow() == False:
+            if f.GetNextRow() == False:
                 raise StopIteration
             for col in self._registered_cols: