[RESOLVED] A Number or Currency Amount is Required Here

[Vacation]

I am running Crystal Reports 10.

My formula is as follows:
{Subscriptions.PAYMENT_AMOUNT} <> ['0.00', '465.00', '515.00']

but I am getting the error "A number, or currency amount is required here."

This is a number field, from what I can tell, but obviously, I'm missing something.

Thanks for any help.