I think that you can get it from:
https://github.com/osTicket/osTicket-1.7/tree/release(https://github.com/osTicket/osTicket-1.7/tree/release)
If not then you can get it from:
http://tmib.net/files/osTicket-1.7.0.zip(http://tmib.net/files/osTicket-1.7.0.zip)
It would also be nice if you posted what issues you experienced and file bug reports at github.
Also you might try the 1.7.1.1 release which has some hot fixes for several issues. Its available here:
https://github.com/osTicket/osTicket-1.7/tree/v1.7.1.1(https://github.com/osTicket/osTicket-1.7/tree/v1.7.1.1)