I looked at
https://bugs.dokuwiki.org/index.php?do=details&task_id=2345 and can confirm this bug does not apply to me as no data is ever saved to the dokuwiki data directory.
After examining the error logs, this message appears in my apache error logs:
[Tue Apr 24 14:42:58 2012] [error] [client BLAH] PHP Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 33032001 bytes) in Unknown on line 0, referer:
https://BLAH.org/doku/doku.php/it:samba?do=media
So, I increased the memory limit in php.ini to 128M from 32M. The same error appears:
[Tue Apr 24 14:45:36 2012] [error] [client BLAH] PHP Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 87962417 bytes) in Unknown on line 0, referer:
https://BLAH.org/doku/doku.php/it:samba?do=media
Interestingly enough, when I change the limit 256M, the error message changed slightly:
[Tue Apr 24 14:55:37 2012] [error] [client BLAH] PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 311296 bytes) in /var/www/html/tools/doku/inc/utf8.php on line 1025, referer:
https://BLAH.org/doku/doku.php/it:samba?do=media