while installation starts in nokia store, suddenly open x-plore and open 'Installs' folder there u can see the setup file ..quickly move it to any other folder 
Install folder in C (Phone Memory) or E (Mass Memory)?
I have installed it,
did it exactly as instructed. (only that i deleted some more applications such as Ovi Music, etc to free up memory).
After finish flashing the phone, first time boot. some message showed up "2 Application installed, 1 error" and "System Error"
I bet it's the Belle Shell app that I fuse with the ROFS2 that's not installed properly.
so, i restarted the phone, connected it with OVI Suite Mode, then installed Belle Shell manually.
Now, it worked all fine (it can launch automatically in startup). The problem is every time I boot up the phone, a message showed up "System Error"
Can anybody help me?