"network-manager roams to (none) ((none))" has already been reported as bug #291760, however it appears to be a harmless message related to losing the connection to the AP (at least with the latest ath5k driver).
"network-manager roams to (none) ((none))" has already been reported as bug #291760, however it appears to be a harmless message related to losing the connection to the AP (at least with the latest ath5k driver).