Same for me, ED and me are throwing support tickets at each other to get it resolved.
I bought the KA50 back in 2008 or so, upgraded to BS2 and within 1.5 I can't get the module installed through the module manager as it states I need BS1 activated but I can start and fly within BS1 with no problems.
With 1.2.16, no problems using BS2 module, under 1.5 I can install the BS2 module but can't activate it as it states it can't accept my upgrade key...