As per the given information, ABC Inc has entered into a contract with a US bank to convert its US dollar purchases for the year 2008 into Indian rupees at a fixed exchange rate of US dollars 1 = Rs. 64.80. The contract is essentially a forward contract.

To determine if it is a derivative contract, we need to apply the definition of a derivative. According to IAS 39, a derivative is a financial instrument or other contract with all three of the following characteristics:

1. Its value changes in response to the change in a specified interest rate, financial instrument price, commodity price, foreign exchange rate, index of prices or rates, credit rating or credit index, or other variable.
2. It requires no initial investment or an initial investment that is smaller than would be required for other types of contracts that would be expected to have a similar response to changes in market factors.
3. It is settled at a future date.

In this case, the contract meets all three criteria of a derivative contract:

1. Its value changes in response to the change in a specified variable, i.e., foreign exchange rate.
2. No initial investment is required for this contract.
3. Settlement of the contract will happen in the future.

Therefore, the contract entered into by ABC Inc with the US bank to convert its US dollar purchases for the year 2008 into Indian rupees at a fixed exchange rate of US dollars 1 = Rs. 64.80 is a derivative contract.

Calculation:

Assuming that ABC Inc's US dollar purchases for the year 2008 is $10 million, the amount of Indian rupees that ABC Inc will receive after conversion is:

$10 million x Rs. 64.80 = Rs. 648 million.