Are you saying that your agents are getting logged out when they post a reply?If so please see:http://forum.osticket.com/d/discussion//resolved-logged-out-when-submitting-ticket-updates

You would have to check your logs and see if there is an error some where which indicates why it cannot lock the ticket. (Mysql, PHP, webserver)

You told us that you were having a CSRF token error in the osT syslog.A CSRF token is a value inserted into a form.  The server expects the token back when that form is submitted.  If the token is not returns or does not match then there is a security issue.  Why are you getting that?  No idea other than the generic that your token doesn't match the one that the server sent you. If you are running SELinux or mod_security or something like that I would investigate those first.  You might also want to make sure that the time/timezone is correct in all places: server, MySQL, PHP, and osTicket.As stated above "You would have to check your logs and see if there is an error some where which indicates why it cannot lock the ticket. (Mysql, PHP, webserver)"I asked you to look at three different logs and you tell me there are no SQL errors and show us a DB table check.  None of that is the SQL logs, the Apache logs, or the PHP error logs. I can tell you that 1000s of people have installed osTicket and not had the issues that you are saying you have.>In admin panel with an open ticket:- cannot delete the ticketDoes your account have permissions to delete tickets?> When changing ticket state from open to resolve get errors: " unable to lock the ticket"> Ticket setting and options, Lock Semantics set to disabled,> attempt to change ticket state get errors: "This operation requires a lock."Aren't sure. I don't know anyone that has this disabled. Does re-enabling make the error go away? (say by setting it to "Lock on activity").  You may have discovered a bug.  I've asked the devs to take a look at this thread to see if they have any additional insight to the issues that you are having.