diff --git a/youtube-dl b/youtube-dl
old mode 100755
new mode 100644
index 231b95c1b..b099ffd15
--- a/youtube-dl
+++ b/youtube-dl
@@ -1967,11 +1967,10 @@ class YoutubePlaylistIE(InfoExtractor):
 				break
 			pagenum = pagenum + 1
 
-		playliststart = self._downloader.params.get('playliststart', 1)
-		playliststart -= 1 #our arrays are zero-based but the playlist is 1-based
-		playlistend = self._downloader.params.get('playlistend', -1) #last item of video_ids is not used
-		video_ids = video_ids[playliststart:playlistend] #always use slice as options have default values
-			
+		playliststart = self._downloader.params.get('playliststart', 1) - 1
+		playlistend = self._downloader.params.get('playlistend', -1)
+		video_ids = video_ids[playliststart:playlistend]
+
 		for id in video_ids:
 			self._youtube_ie.extract('http://www.youtube.com/watch?v=%s' % id)
 		return
@@ -2027,10 +2026,9 @@ class YoutubeUserIE(InfoExtractor):
 				ids_in_page.append(mobj.group(1))
 		video_ids.extend(ids_in_page)
 
-		playliststart = self._downloader.params.get('playliststart', 1)
-		playliststart -= 1 #our arrays are zero-based but the playlist is 1-based
-		playlistend = self._downloader.params.get('playlistend', -1) #last item of video_ids is not used
-		video_ids = video_ids[playliststart:playlistend] #always use slice as options have default values
+		playliststart = self._downloader.params.get('playliststart', 1) - 1
+		playlistend = self._downloader.params.get('playlistend', -1)
+		video_ids = video_ids[playliststart:playlistend]
 
 		for id in video_ids:
 			self._youtube_ie.extract('http://www.youtube.com/watch?v=%s' % id)
@@ -2242,16 +2240,18 @@ if __name__ == '__main__':
 				opts.retries = long(opts.retries)
 			except (TypeError, ValueError), err:
 				parser.error(u'invalid retry count specified')
-		if opts.playliststart is not None:
-			try:
-				opts.playliststart = long(opts.playliststart)
-			except (TypeError, ValueError), err:
-				parser.error(u'invalid playlist-start page specified')
-		if opts.playlistend is not None:
-			try:
-				opts.playlistend = long(opts.playlistend)
-			except (TypeError, ValueError), err:
-				parser.error(u'invalid playlist-end page specified')
+		try:
+			opts.playliststart = long(opts.playliststart)
+			if opts.playliststart <= 0:
+				raise ValueError
+		except (TypeError, ValueError), err:
+			parser.error(u'invalid playlist start number specified')
+		try:
+			opts.playlistend = long(opts.playlistend)
+			if opts.playlistend != -1 and (opts.playlistend <= 0 or opts.playlistend < opts.playliststart):
+				raise ValueError
+		except (TypeError, ValueError), err:
+			parser.error(u'invalid playlist end number specified')
 
 		# Information extractors
 		youtube_ie = YoutubeIE()