I get these error entries approximately in 20 minute intervals in the 

C:\ProgramData\SqueezeCenter\Logs\server.log

file:

".. Slim::Networking::SqueezeNetwork::PrefSync::_syncDown_error (359) Sync Down failed: No such player: 00:04:20:07:80:98, will retry in 1650 .."

Only once (after I tried to xsolve the issue by installing the 113 7.2.1 firmware for the SB3 again) did it report the exact same error syntax, but with a 576 code instead of 359.

I should point the MAC identifies is the only SB3 in an environment that also includes 2 Sbooms and 1 Duet. Only the SB3 reports these, and that despite the fact that it seems to be operating flawlessly.

I should also point out that the only reason why I checked the logfile was because suddenly I started to experience odd issues in SC responsiveness - I'd a loooooong initial reponse lag from whatever device I was trying to use. It seems that through reinstall of SC 7.2.1 I reset that issue, hwoever I wonder whether an accumulation of this reported error over a few weeks could cause the reponsiveness issue again (pure speculation). I attach my entire log file. The firmware update was done at about 9.21am, and I should note I was also doing stuff on the other devices only none of them reports anything worthwhile.

Here also the status information in SC:

SqueezeCenterSqueezeCenter Version: 7.2.1 - 23630 @ Tue Oct 21 07:44:57 PDT 2008 - Windows Vista - EN - cp1252
Server IP address: 192.168.1.10
Perl Version: 5.8.8 MSWin32-x86-multi-thread
MySQL Version: 5.0.22-community-nt 
Platform Architecture: 586
Hostname: Pablo-ServerV64
Server Port Number: 9000

Total Players Recognized: 4

 
Player InformationName: Bedroom
Model: receiver
Firmware: 48
The IP address for this player is: 192.168.1.105:37747
The Ethernet MAC address for this player is: 00:04:20:16:30:f6
Wireless Signal Strength: 30

Name: GymBoom
Model: boom
Firmware: 33
The IP address for this player is: 192.168.1.29:16781
The Ethernet MAC address for this player is: 00:04:20:1e:12:54
Wireless Signal Strength: 87

Name: KitchenBoom
Model: boom
Firmware: 33
The IP address for this player is: 192.168.1.106:49443
The Ethernet MAC address for this player is: 00:04:20:1e:1b:80
Wireless Signal Strength: 46

Name: LivingRoom
Model: Squeezebox v3
Firmware: 113
The IP address for this player is: 192.168.1.107:27880
The Ethernet MAC address for this player is: 00:04:20:07:80:98
Wireless Signal Strength: 73