Suresh,
The PMBOK Guide fifth edition was published in December 2012 and the PMP Exam will change on July 31st, 2013. So if you are planning to take the exam BEFORE this date... no problem. You can use PMBOK v4 and PrepCast for v4.
However... if you are taking the exam ON or AFTER this date, then you must use everything for PMBOK v5.
If you need to access & download the current PrepCast again, then please write to This email address is being protected from spambots. You need JavaScript enabled to view it. and the team will help you to access your account again. (We changed to a new system in 2011, so your old account is no longer active and we'll create a new one for you if you need it.)