Dear Reggie,

Thank you for your reply. After a AE reset and firmware flash and an N800 firmware flash, the problem is still there... The macs cause no hang at all when they are alone...

Could it be a problem of my mixture of Router + AE ?

here the is the log... not many useful infos...

Jul 15 15:58:01 Severity:5 Initialized (firmware 7.1.1).
Jul 15 15:58:02 Severity:3 No Address for NTP server time.euro.apple.com.
Jul 15 15:58:05 Severity:5 Internet Configuration leased (host 192.168.1.34/255.255.255.0 gateway 192.168.1.1 dns 208.67.222.222 208.67.220.220 lease 86400 domain )
Jul 15 15:58:06 Severity:5 Deauthenticating with station ff:ff:ff:ff:ff:ff (reserved 3).
Jul 15 15:58:06 Severity:5 Rotated TKIP group key.
Jul 15 15:58:07 Severity:5 Associated with station 00:19:e3:31:c6:cd
Jul 15 15:58:07 Severity:5 Installed unicast CCMP key for supplicant 00:19:e3:31:c6:cd
Jul 15 15:58:10 Severity:5 Internet Configuration leased (host 192.168.1.34/255.255.255.0 gateway 192.168.1.1 dns 208.67.222.222 208.67.220.220 lease 86400 domain )
Jul 15 15:58:17 Severity:5 Associated with station 00:17:f2:e9:f6:1e
Jul 15 15:58:17 Severity:5 Clock synchronized to network time server time.euro.apple.com (adjusted +3 seconds).
Jul 15 15:58:17 Severity:5 Installed unicast CCMP key for supplicant 00:17:f2:e9:f6:1e
Jul 15 15:58:28 Severity:5 Connection accepted from fe80::217:f2ff:fee9:f61e%bridge0/57199.
Jul 15 15:58:32 Severity:5 Connection accepted from fe80::217:f2ff:fee9:f61e%bridge0/57203.
Jul 15 15:59:04 Severity:6 Parameter updated - syNm.
Jul 15 15:59:04 Severity:6 Parameter updated - syPW.
Jul 15 15:59:04 Severity:6 Parameter updated - syPR.
Jul 15 15:59:04 Severity:6 Parameter updated - syCt.
Jul 15 15:59:04 Severity:6 Parameter updated - syLo.
Jul 15 15:59:04 Severity:6 Parameter updated - syRe.
Jul 15 15:59:04 Severity:6 Parameter updated - syIg.
Jul 15 15:59:04 Severity:6 Parameter updated - time.
Jul 15 15:59:04 Severity:6 Parameter updated - timz.
Jul 15 15:59:04 Severity:6 Parameter updated - wbEn.
Jul 15 15:59:04 Severity:6 Parameter updated - wbHN.
Jul 15 15:59:04 Severity:6 Parameter updated - wbHU.
Jul 15 15:59:04 Severity:6 Parameter updated - wbHP.
Jul 15 15:59:04 Severity:6 Parameter updated - wbRD.
Jul 15 15:59:04 Severity:6 Parameter updated - wbRU.
Jul 15 15:59:04 Severity:6 Parameter updated - wbRP.
Jul 15 15:59:04 Severity:6 Parameter updated - 6aut.
Jul 15 15:59:04 Severity:6 Parameter updated - prnR.
Jul 15 15:59:04 Severity:6 Parameter updated - SMBw.
Jul 15 15:59:04 Severity:6 Parameter updated - SMBs.
Jul 15 15:59:04 Severity:6 Parameter updated - fssp.
Jul 15 15:59:04 Severity:6 Parameter updated - cver.
Jul 15 15:59:04 Severity:6 Parameter updated - ctim.
Jul 15 15:59:04 Severity:6 Parameter updated - Prof.
Jul 15 15:59:04 Severity:6 Parameter updated - leAc.
Jul 15 15:59:04 Severity:6 Parameter updated - AAU .
Jul 15 15:59:04 Severity:5 Configuration updated.
Jul 15 15:59:04 Severity:6 Parameter updated - acFN.
Jul 15 15:59:04 Severity:6 Parameter updated - acRI.
Jul 15 15:59:04 Severity:5 unloading current configuration.
Jul 15 15:59:13 Severity:3 No Address for NTP server time.euro.apple.com.
Jul 15 15:59:16 Severity:5 Internet Configuration leased (host 192.168.1.34/255.255.255.0 gateway 192.168.1.1 dns 208.67.222.222 208.67.220.220 lease 86400 domain )
Jul 15 15:59:17 Severity:5 Deauthenticating with station ff:ff:ff:ff:ff:ff (reserved 3).
Jul 15 15:59:18 Severity:5 Rotated CCMP group key.
Jul 15 15:59:19 Severity:5 Associated with station 00:19:e3:31:c6:cd
Jul 15 15:59:19 Severity:5 Installed unicast CCMP key for supplicant 00:19:e3:31:c6:cd
Jul 15 15:59:29 Severity:5 Clock synchronized to network time server time.euro.apple.com (adjusted +1 seconds).
Jul 15 16:02:26 Severity:5 Associated with station 00:17:f2:e9:f6:1e
Jul 15 16:02:26 Severity:5 Installed unicast CCMP key for supplicant 00:17:f2:e9:f6:1e
Jul 15 16:02:36 Severity:5 Connection accepted from fe80::217:f2ff:fee9:f61e%bridge0/57228.
Jul 15 16:02:40 Severity:5 Connection accepted from fe80::217:f2ff:fee9:f61e%bridge0/57232.
Jul 15 16:02:45 Severity:5 Associated with station 00:19:4f:d4:ec:6d
Jul 15 16:02:45 Severity:5 Installed unicast CCMP key for supplicant 00:19:4f:d4:ec:6d