Hello,
PayPal supports not all values, if you want use paypal - you need add only that values, which paypal supports,
www.paypal.com/multicurrency - PayPal 's Multiple Currencies features
developer.paypal.com/docs/classic/api/currency_codes/ - this code need put in field of Real Estate.
Or If You do not need PayPal - you can turn off it and add any value in Currency field.
(RealEstateManager : Settings - Administrator Settings - Price Options - Currency)
For turn off PayPal: RealEstateManager :: Payment settings -
Show buy for booking: NO
Show buy for sale: NO
Thanks,
Taras