well i just simply installed Squeeze 6.0.7 like i use to do it. however in old days i was using windows XP CD to delete the partition however this time i decided to delete partition via FDISK during installation and i have used fdisk for very long so there are less chances of making mistakes. i surely remeber that i deleted all the partition via fdisk and manually recreated the partition in installation process where it ask manually partitioning the disk.
so thats all i did.
btw, one more thing my partition tables were a bit advance where i used RAID and LVM, do you think it could be the reason of that?