To all of those that have posted about their trouble free play back on your Blu ray players - brilliant, you have been lucky.
But, this does happen on various players / different brands all of the time. So to think that it does not ever happen is just being a bit naive. You just need to trawl this Blu ray sections forum and you will find loads of examples of this.
My advice, if it is still under warranty (your player) would be to take it back to where you bought it to get a replacement if possible. This seems to happen on an alarming occurance. Never had these issues with dvd players (well certainly not as much). All electronics go wrong from time to time, so many different components that could be at fault.
I speak from experience and I am not slagging off the format, some have been lucky and others like myself and the posts above have not. My Panasonic BDP 500 was awful (a flagship player) as was my Sony BDP S370 (do a search on this forum and it is not just me). I replaced my Panasonic with a 790 and so far it has been faultless but it is still early days, the 370 is in our bedroom so not such an issue.
This makes an interesting read - and panasonic still have not returned the player fixed to Richer Sounds weeks and weeks on (pop in regularly to local store).
http://www.whathifi.com/forum/blu-ray-players/panasonic-dmp-bdt-500-got-issues