I'm using latest NextGen Gallery plugin and I'm experiencing random bug. I'm seeing random errors on thumbnail creation. After monitoring ajax request I discovered that ajax request isn't returning anything. When request is successful, then HTTP 200 is returned, but randomly nothing isnt returned from admin-ajax.php.
I made some screenshots:
http://dl.dropbox.com/u/26667345/nextgen_error_1.PNG - shows image id and error message
http://dl.dropbox.com/u/26667345/nextgen_error_2.PNG - requests made by script, n/a is the problematic one.
http://dl.dropbox.com/u/26667345/nextgen_error_3.PNG - problematic request
http://dl.dropbox.com/u/26667345/nextgen_error_4.PNG - this is successful request.