ATA error log entry

I am unsuccessfully trying to use post-expirator plugin.
My very-very many searches for why it is not working has shown me error log entries in my hosting company (cloudnext) admin panel which show ATA bringing about an error.

I do not know if the ATA error has anything to do with the plugin problem, but the error occurs when I put up a new post and select post expirator to either delete or change to draft at a future time.

Plugin Co is telling me "must be hosting co fault" & hosting Co are telling me; i'll let you guess !!

However I would welcome someone looking at the following errors and telling me if they mean anything of significance:- (the error messages stop when I change theme to TwentyTwelve)

Error Logs
[Sat Apr 06 12:30:43 2013] [error] [client 90.xxx.85.xxx] PHP Notice: Undefined index: bfa_ata_noncename in /home/sites/xxxsitename.co.uk/public_html/wp-content/themes/atahualpa/functions.php on line 665, referer: http://www.xxxsitename.co.uk/wp-admi...edit&message=6
[Sat Apr 06 12:31:14 2013] [error] [client client 90.xxx.85.xxx] PHP Notice: Undefined index: bfa_ata_noncename in /home/sites/xxxsitename.co.uk/public_html/wp-content/themes/atahualpa/functions.php on line 665, referer: http://www.floodproblems.co.uk/wp-admin/post-new.php

Access Logs
xxxsitename.co.uk client 90.xxx.85.xxx - - [06/Apr/2013:12:31:37 +0100] "GET / HTTP/1.1" 200 186037 "http://www.xxxsitename.co.uk/wp-admin/options-general.php?page=post-expirator.php" "Mozilla/5.0 (Windows NT 6.1; rv:19.0) Gecko/20100101 Firefox/19.0"