Error 1054! Unknown column 'a.modified_date' in 'o

Hi,
I'm using helpdesk in the latest version. All good so far apart from the menu link that should show a list of the tickets. It produces the following SQL error:

Error
1054!
Unknown column 'a.modified_date' in 'order clause....

I can't paste the complete error code here, because your system tells me that I try to inject some SQL.

What can I do?
Thanks
Roger

Here are my 2 cents...
1054 typically indicates that there is a missing data element, 'a.modified_date', in table mentioned. A query will follow the error message showing each field being gathered from the table. Use PHPMYADMIN or something similar to check each of these fields to ensure that the table listed in the error message has every field listed. If a data element is missing, create it and see if that fixes your issue.