Same issue here. On WP 3.3.1
Find posts after long search. Find works perfectly, but takes like 20 min for 2000 posts to find. Than to delete only first 100 took another 20 min. And than nothing. Blank screen, no way to continue even. Back to step one - searching for duplicated posts... that way it's too slow. it's faster to remove them manually :(
Otherwise great idea and works perfectly in finding duplicated posts. If you fix it - it would be awesome plugin!
@yoramzara - how i can get old version from you to test? can you please email me on: myozus (at) gmail (dot) com?