Cant get into my site after trying to install Sobi2 plugin

Ok, I was trying to install Sobi2 media plugin. It did not work. I kept getting an error. In the media folder created in the media manager it said it was a permissions error. After doing some research and getting no help, I changed some permissions in a few folders...like php.ini. I set it to 777. Now I cant get in my site from the back end. I enter the admin name and password and the screen just refreshes. Its not a password issue or else it would say password is wrong, nothing happens at all, there is something else wrong. I am a novice and wouldnt begin to know what it is. Did some searches and didnt find anyone with a similar problem. I need help, plus I need this Sobi2 issue sorted out. I need the media manager to work so that I can have users upload and download mp3's to pages. I need someone IMMEDIATELY!!! If you can not do this job TODAY, please do not bid. If I select you and you cant start TODAY, I have to find someone else. Thanks.