It's implemented here and, well, I think the problem is obvious. It throws up th is error:
Warning: mkdir(): SAFE MODE Restriction in effect. The script whose uid is 571 is not allowed to access /home/virtual/site68/fst/var/www/html/wp-content/af-extended-live-archive owned by uid 48 in /home/virtual/site68/fst/var/www/html/wp-content/plugins/af-extended-live-archive/af-extended-live-archive.php on line 223
Could not create cache. Make sure the wp-content folder is writable by the web server.
The folder in question, is definitely writable. I CHMODded it to 777, just to be sure, and it still throws up the same error.
Did a quick search, but couldn't find any mention of this problem before.
Any suggestions would be massively appreciated.