First thing is I'm pretty sure that the Foxtel IQ network encrypt their recordings so you won't be able to convert them to playable MPEG2 files.
When you fire up +Extract, what colour are the icons beside the recordings? Green = clear, Red = Encrypted and Orange = undetermined.
If the recordings are clear then try using ProjectX to convert the .STR extracted files. If ProjectX complains about not finding 'sequence_header' then the recording is definitely encrypted.