Check that you have entered the correct email address in your listings. In your Sold section hover over the blue dollar sign and it should show which email address any payments have gone to.
Is your paypal account a Personal account? If it is, you will need to upgrade it to a Premier account to accept payments.
At the top under where it says Welcome, it shows the account type with a link to upgrade.
More info
http://pages.ebay.com.au/help/pay/paypal-upgrade.html