Hey buddy I was having the same problem.
I tried to change the name of the theme folder in ftp(it get automatically set to default) and then i tried to login. I could then login to the wordpress admin area and there i notice the theme automatically gets set to default. When I try to set to a particular theme, the blog pages do work but then I am not able to login to the admin area.
Help would be really really appreciated.
Please mail me the solution at vinayvasyani@gmail.com.
