Hi,
You need to search for the script that inserts this context. Try to run this command in your Linux console:
fgrep -R thankuohoh /etc
I have a feeling that you are using Elastix and it suppose to be in the /etc/asterisk_extensions_custom.conf file. Make sure to delete this file and the references to this file in the asterisk directory (more details here). If you are using also the A2Billing in this version of Elastix please make sure that you will read this link.
Basically, it means that you have to search the file that gives admin permissions to Elastix portal. The file's name is A2B_php_stats.php. Make sure to delete this file and to correct the admin/Public/A2B_entity_restore.php file.
Thank you,
Daniel Friedman
Trixton LTD,