Fatal error: Cannot redeclare cforms_activate() (previously declared in /home/public_html/wp-content/plugins/cforms/cforms.php:59) in /home/public_html/wp-content/plugins/cforms/cforms.php on line 61
I had a similar error when upgrading to version 10.5.1 & 10.5.2 of cforms.
If like me you did not read the upgrade notes dooh!!! and just tried uploading the zip file in the plugins admin then it will create a folder in the route of your plugins called Patch 10.5.1 which has a cforms php file. So 2 files exist and cforms will not activate. Delete this Patch folder and ftp all the upgrade files into your original cforms folder.