After being passed over to Paypal for payement you can click on a text link that says 'Cancel order and return to website' (or something very similar). After clicking this I get a magento page saying:
Exception printing is disabled by default for security reasons.
Error log record number: 168841030658
This error then keeps appearing even if I retype the website address manually, until I clear the cache of the browser.
Any help would be welcome.