Migration from 1.7.2 to 2.0 and respectively to 3.0

Hello guys. 
I have the task to migrate a codeigniter webpage from 1.7.2 to 2.0 ( 2.2 ) and then I need to migrate it to 3.0. 
I followed this particular guide: http://www.codeigniter.com/user_guide/in...e_200.html
And after I did everything I uploaded it to the ftp and now I am getting a blank page. 
I think I've got all things done as by the tutorial but even if I have missed something I at least need an indication for that. But I am getting nothing - blank page. 
I enablet error_reporting - nothing 

Configed the log_treshhold to 1, and again - nothing 

It's very important so pls, help me. 

Best regards, 
g3n1u5

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