diff --git a/oletools/olevba.py b/oletools/olevba.py
index 789c995..f8b7f76 100644
--- a/oletools/olevba.py
+++ b/oletools/olevba.py
@@ -2532,7 +2532,7 @@ class VBA_Parser(object):
             self.ole_file.close()  # just in case
             self.ole_file = None   # required to make other methods look at ole_subfiles
             self.type = TYPE_PPT
-        except Exception as exc:
+        except (ppt_parser.PptUnexpectedData, ValueError) as exc:
             if self.container == 'PptParser':
                 # this is a subfile of a ppt --> to be expected that is no ppt
                 log.debug('PPT subfile is not a PPT file')
diff --git a/oletools/ppt_parser.py b/oletools/ppt_parser.py
index 2a8cb37..450ded2 100644
--- a/oletools/ppt_parser.py
+++ b/oletools/ppt_parser.py
@@ -40,12 +40,7 @@ import struct
 import traceback
 import os
 
-try:
-    # absolute import when oletools is installed
-    import oletools.thirdparty.olefile as olefile
-except:
-    # relative import otherwise
-    import thirdparty.olefile as olefile
+import thirdparty.olefile as olefile
 
 import zlib
 
@@ -1130,7 +1125,7 @@ class PptParser(object):
             log.debug('using open OleFileIO')
             self.ole = ole
         else:
-            log.debug('Opening file ' + ole)
+            log.debug('Opening file {0}'.format(ole))
             self.ole = olefile.OleFileIO(ole)
 
         self.fast_fail = fast_fail