You might try googling:
PHP Warning: mail(): Failed to connect to mailserver at "localhost" port 25, verify your "SMTP" and "smtp_port"
The error that you are receiving is a PHP error, not a osTicket error. Open up your php.ini and look for "" or "SMTP". You should find something like:
; For Win32 only.
SMTP = emailserver.name.com
smtp_port = 25
As a side note if you do not have a mail server that you can use for this, there are alternatives. We ran IndigoMail (Sendmail for windows) for a while.
http://www.indigostar.com/indigomail.php(http://www.indigostar.com/indigomail.php)
You might also make sure that any firewalls you have (including the native windows one on your webserver) isn't blocking the following ports: 993 (imap), 465, 587 (smtp auth). If you can use telnet on the webserver to test them.
imap.gmail.com
Use SSL: Yes
Port: 993
smtp.gmail.com (use authentication)
Use Authentication: Yes
Use STARTTLS: Yes (some clients call this SSL)
Port: 465 or 587
Good luck!