When I try to get PDF statistics for any survey (that I've tried, anyway), I get nothing. Opera tells me "connection closed by server" and says the page was unavailable. Firefox just gives me a blank page. Web server logs give me nothing, either.

Can anyone suggest things I should look at?

Limesurvey version:

$versionnumber = "1.90+";
$dbversionnumber = 143;
$buildnumber = '9487';

PHP settings:

max_execution_time = 90
max_input_time = 90
memory_limit = 356M

(I had to bump that last one up for a different, not limesurvey-related, issue.)

$memorylimit (config-defaults.php) is 64M

Thanks,
Kyle