As far as my knowledge goes,
Dividend Amount has to be deposited within 5 days from the date of the declaration into a separate bank account in a scheduled bank.
Dividend Warrants and payment of the dividend has to be made within 30 days from the date of the declaration and approval at the AGM.
Dividend unclaimed lying in the Dividend Account even after expiry of 30 days has to transferred to Unclaimed Dividend Account within 7 days from the expiry of aforesaid 30 days
And lastly Dividend unclaimed lying in the unclaimed Dividend Account for period of 7 years has to be transfered to IEPF
Note.: As the new Company Law Bill 2008 which is in the conduit of being passed as an enactment does not provide for transfer of the Dividend Unclaimed to IEPF even if it is lying in the Unclaimed Dividend Account from many years.
Good Luck ......