After along struggle I have finally managed to overcome the Error 503 problem.
What I did was to uninstall all the earlier versions including all the backups. I also had to up grade the Firefox browser from 13 to 14
I then did a fresh installation of the software the latest version of frontlinesms version 2.0.3 I rebooted the Pc and finally I had it working.
Unfortunately I lost all the contacts and the messages. Anyway am happy to see that it is now working properly. However am not certain if it will not crash again