I installed the latest release (1.2) of the DataTransfer Extension via Git. I installed it on a 1.31 MW system per the INSTALL file. I went to the Spezial:XMLview page as instructed. I selected one of the  categories and the main namespace and hit 'view XML'. After a few seconds (< 10) I got a 500 page. I see the 500 error in the PHP logs (so this isn't a web timeout). The PHP debug logs show only the following: