I just went to the github site as adviced on this forum by the author, downloaded the code and updated my server thinking surely its had all the bugs removed, well guess what, nothing works now, all i get is a 500 Error.
I have decided to start again from a fresh web app and document my progress to keep track of what is going on.
Not cool indeed.
well first, we always need to do a backup before doing an upgrade (you are sure you don’t have any back up?) and I think the best way to do is to making it work locally and after uploading it to the server.
You should check for changes before starting an upgrade:
http://www.yiiframework.com/files/UPGRADE-1.1.8.txt
I hope you will find what is the problem rapidly, I’m sure it’s just a little thing 
Well i would like to tell you that if you are much familiar with Linux environment then surely you get rid off from this problem… 
.
Error code 500 show the permission problem to directory.it is not any issue of code 
Give a permission to chmod 777 or 755 to directory then lets check…everything will work…