It was the other name of Kuvera. Kuvera was called Ailavila many times in Mahābhārata.
According to the Kūrma Purāṇa, Kuvera was born in the womb of Ilavilā, the daughter of sage Triṇavindu. Sage Pulastya was the father of Kuvera. As the son of Ilavilā, Kuvera was known as Ailavila..