That looks like an extra file that isn't part of the standard installation - you must have copied that at some time in the past for some reason. Its a Bouncy Castle Crypto package that you must have needed for that code. It should be safe to copy as jar files are bit length independent. The worst that can happen is it doesn't work
Thanks for the reply - it happens that I was just snuffling around when your reply arrived.
It seems that its related to KeyValueStore (gleaned indirectly out of a posting search) and (I guess) should be included with the install of B4J-64. I say that because its in the Libraries folder of B4j-32.
I just first removed KeyValueStore library from the list and then compiled which went fine. I just copied it over, compiled with KVS included and it worked fine.