5.2 is very old. I know you won't like this answer but if you have the DB programming software you can always default the CPU and re-key it. If you do not have experiance to program find a good dealer that will take this on. DND ON is right. Mitel has cut off all support on Inter-tel Axxess unless you have a version 10 or 11 and that will end in a few months. Tough to see a good system get a cap busted into it.
Inter-tel Axxess, Mitel CS/HX5000, MiVoice Office CCS/CSM, VPU, EM, ATM4, A+, CTP+, NET+, OAISYS, Audicodes, Polycom, Spectralink, NEC Red, Samsung, Mitel Call Recording, Mitel MBG, MiVoice Office, Xarios. Mitel Phone Manager