After upgrading from MacOS 9.2.1 to 9.2.2 VW 8.5.1 will not open . You get en error massage: "The application "VectorWorks 8.5.1" could not be opened because an unexpected error occured (-2,817). As soon as I reinstalled MacOS 9.2.1 the problem solved and everthing works fine again.
(Luckily I had the sytem folder backed -up before upgrading to 9.2.2)