in logging events i detected that :
Mar 12 10:12:05 192.168.10.10 638: 01:47:36: dot1x-ev:Received VLAN is No Vlan
and after
Mar 12 10:12:05 192.168.10.10 673: 01:47:36: dot1x-ev:Received VLAN Id -1
but, this problem is in IAS server..or the cisco that not can get the vlan id tag ???