Index: programs/mythfrontend/playbackbox.cpp
===================================================================
--- programs/mythfrontend/playbackbox.cpp	(revision 13319)
+++ programs/mythfrontend/playbackbox.cpp	(working copy)
@@ -4003,7 +4003,7 @@
  */
 bool PlaybackBox::SetPreviewGenerator(const QString &xfn, PreviewGenerator *g)
 {
-    QString fn = xfn.mid(xfn.findRev('/') + 1);
+    QString fn = xfn.mid(max(xfn.findRev('/') + 1,0));
     if (!g)
     {
         if (previewGeneratorLock.tryLock())
@@ -4032,7 +4032,7 @@
     QMap<QString, PreviewGenerator*>::const_iterator it;
     QMutexLocker locker(&previewGeneratorLock);
 
-    QString fn = xfn.mid(max(xfn.findRev('/'),0));
+    QString fn = xfn.mid(max(xfn.findRev('/') + 1,0));
     if ((it = previewGenerator.find(fn)) == previewGenerator.end())
         return false;
     return *it;
@@ -4045,7 +4045,7 @@
 uint PlaybackBox::IncPreviewGeneratorAttempts(const QString &xfn)
 {
     QMutexLocker locker(&previewGeneratorLock);
-    QString fn = xfn.mid(max(xfn.findRev('/'),0));
+    QString fn = xfn.mid(max(xfn.findRev('/') + 1,0));
     return previewGeneratorAttempts[fn]++;
 }