You driver does not implement that method. To fix this you can hunt around for a suitable driver that does - I'm afraid I have no idea if one exists for Sybase - or you can change your logic to achieve what you want.
I think you are right that it does not exist for sybase. Could you please suggest some logic because i need to come out of the loop once i reach the last row? I don't know how will i come to know if i have reached to the last row without using isLast method. Please help.