i'm getting somewhat the same problem, but it seems to load ok on the first start of a logic file. if for any reason i have to close and re-open logic, i get the "can't open plugin" error on the slave mac, not the host, unless i close and re-open the server before re-opening logic.
dan
logic 9.1.1 64 bit-vep host machine-10.6.3
vep 64 bit slave machine-10.6.3