Hi,
That's weird. Normally it should just say: "Cart".
Did you manually change the "translation" ?
Open this INI file:
/components/com_virtuemart/language/en-GB/en-GB.com_virtuemart.ini
Make sure, this line is exist:
COM_VIRTUEMART_CART_TITLE="Cart"
Most likely yours is like this (which is wrong):
COM_VIRTUEMART_CART_TITLE="Your Cart is Empty"
so, make the correction.
Regards,
Support