Warnings are corrected

pymolfile/pymolfile.py

@@ -514,7 +514,7 @@ class OpenMolfile(object):
                             else:
                                 warnings.warn("Pymolfile can not find a plugin to open the '" + 
                                       self.kwords["topology_format"] + "' file format of the file " + 
-                                      str(topo_file_base) + "." + str(topo_file_ext))
+                                      self.kwords["topology"])
 
                 if self.fplugin[1][5] == 1:
                     num_atoms = 0
@@ -531,7 +531,7 @@ class OpenMolfile(object):
                                 self.kwords["silent"])
             else:
                 warnings.warn("Pymolfile can not find a plugin to open the '" + self.kwords["file_format"] + 
-                      "' file format of the file " + str(file_base) + "." + str(file_ext))
+                      "' file format of the file " + self.kwords["file_name"] 
 
     def initialize_settings(self):
         #global MOLFILE_PLUGINS