for the "?:0: attempt to index field '?' (a nil value) (call stack not available)" problem I think I already solve this problem. somedays ago I had the same problem when I tried to run Angry birds rio, after searching online for solution but I didn't fine one. I tried to uninstall and re-install the program but its still the problem. then I think I have to solve the problem myself in my my way..
so this what I do :

1. uninstall the program.
2. go to C:\Users\"user name"\apps data\Rovio.
3. delete the 'rovio' folder.
4 re-install the program, and run it, Insyaallah it will run okay.


*this solution work for me, I use Windows 7 Ultimate 32 bit.
*if this also work for you, share this ! cuz there many others who has the same problem and don't have any solution. lets help each other.

if you need to ask me something email me ---> chaleel91@yahoo.com or PM me on facebook ----->http://www.facebook.com/profile.php?id=100000168241457


thanks!