Francisco,
It looks like your HA group password might not match across units. That might be the reason for the " information telnet(10.0.0.3) login User FGT_ha_admin login failed from telnet(10.0.0.3)" message.
Try entering the command " get system status" from the console of each device. My bet is that they will all believe that they are the master. In the output of the " get system status" command you will see something to the effect of:
Version: Fortigate-XXXX 3.00,buildXXXX
(output omitted)
Common Criteria mode: disable
Current HA mode: a-p, master
Distribution: International
Branch point: XXX
System time: Fri Jul 21 12:24:59 2006
Once you get them talking then one should become the master and the others the slaves.
Good luck!