Dmitry is on the case :-) Looks like the app was created with older version of 6.0 beta. I'm going to build my own 6.0 test app and try on my mac today.
Private message replied to - it was one of Barry Beckham's slideshow that I was running - I've not tried PTE 6.0 myself yet. Mac is fully up to date with all patches BTW. Thanks for the quick response. Robert
I've tried running a couple of pte.app shows on my Imac OS 10.6.1 and both have completely locked the system - dark blue screen, no keyboard input. I've had to hard boot the machine both times.