Customer_User_ID problem for Customer Ticket

[MasterLee]

Hi, Guys:
I tried to upgrade my OTRS from 2.4.4 to 3.0.5. I followed instruction on the file in rpm package, however, after I finished my upgration and logined, I found out problems below:

1. all tickets in DashBoard still show up but it will be hanging if I tried to open any one.
2. The Status view in Ticket manu is hanging if I click it.
3. Customer menu is hanging if I click it.
4. In Admin menu, if I click Customer, it will be hanging.

I tried to figured out problem for few days and I found out, if I removed all the entries in Customer_User_ID field in Ticket table in MySQL for all the tickets, then at least I can do no. 1 and no. 2, which means I can start browsing tickets and also reply. However, everything relate to 'Customer' still no work.

Please if any body have got problem relate to 'Customer' something, let me know ...