I was just about to post asking if there was a problem with the latest 2.1.29 and Sub Extraction, only to find it's just been fixed in 2.1.30. Thanks!
Maybe not, just tried a film I recorded this afternoon and when it gets to the ocr stage I get this error
Update: Just tried the same file after restarting TS-Doctor and the SUBS extracted without error.
(http://godmanchester.co.uk/images/capture.jpg)