Dfine 2, for me, will not launch via LR 5.2 on x64 Windows since the update. There is a dump in the application log that I sent to Nik via email.
Not sure if anyone else has the issue or not. Mac version works fine. Stand alone 32-bit works; 64-bit stand alone does not. But neither the 64 or 32 bit versions will launch when invoked from LR.