i try to get the paypal payment run in my magento 1.4 but there is a serious problem with the workflow. after i select paypal and get routed to the paypal account to send the money you normally come back automatically into the magento shop to finish the order, but in my case magento tells you there is aproblem with the adress field. paypal does'nt send the adress back to magento correctly:

Error: Please check shipping address information. Please enter last name.

is this a known bug or is there a patch or workaround?

This thread gives instructions on what causes this and how to fix it.