Try update the WIBU software on the server (and maybe on your Mac). It's good if they are the same.
There should not be a problem having a XP server and local stations with both XP and OSx running on AC 8, 9 or 10 at the same time.
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Susanne, Lasercad Sweden
PB G4 / Mac OS 10.4.8 / AC 9.0 & 10