Actually, I suspect the new Chromium engine. A search found it on my both machines that have MC16 installed. In my case the debug.log files are not on Desktop.
XP:
C:\Documents and Settings\[my username]\debug.log
Created: February 23, 2011, 11:14:26
Modified: February 24, 2011, 11:57:26
The contents:
[0223/113613:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113614:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113614:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113615:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113615:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113616:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113616:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113617:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113617:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113617:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113618:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113618:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113619:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113620:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0223/113655:ERROR:tcp_client_socket_win.cc(423)] connect failed: 10061
[0223/113717:ERROR:tcp_client_socket_win.cc(423)] connect failed: 10061
[0223/113719:ERROR:tcp_client_socket_win.cc(423)] connect failed: 10061
[0223/113725:ERROR:tcp_client_socket_win.cc(423)] connect failed: 10061
[0223/113727:ERROR:tcp_client_socket_win.cc(423)] connect failed: 10061
[0223/113732:ERROR:tcp_client_socket_win.cc(423)] connect failed: 10061
[0223/113734:ERROR:tcp_client_socket_win.cc(423)] connect failed: 10061
[0223/113811:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
[0224/115703:ERROR:backend_impl.cc(1091)] Critical error found -8
[0224/115704:ERROR:tcp_client_socket_win.cc(423)] connect failed: 10061
[0224/115704:ERROR:tcp_client_socket_win.cc(423)] connect failed: 10061
[0224/115704:WARNING:storage_block-inl.h(119)] Failed data load.
[0224/115725:WARNING:tcp_client_socket_win.cc(98)] Unknown error 10004 mapped to net::ERR_FAILED
Windows 7, 32-bit:
C:\Windows\System32\Debug.log
Modifed: February 24, 2011 (if I recall correctly)
I'll post the other details when I am on that machine...
... EDIT, February 28
C:\Windows\System32\Debug.log
Created: February 24, 2011, 13:00:00
Modified: February 24, 2011, 13:22:17
The contents:
[0224/132215:WARNING:backend_impl.cc(1779)] Destroying invalid entry.
[0224/132215:WARNING:backend_impl.cc(1779)] Destroying invalid entry.
[0224/132215:WARNING:backend_impl.cc(1779)] Destroying invalid entry.
[0224/132215:WARNING:backend_impl.cc(1779)] Destroying invalid entry.
[0224/132215:WARNING:backend_impl.cc(1779)] Destroying invalid entry.
[0224/132215:WARNING:backend_impl.cc(1779)] Destroying invalid entry.
[0224/132215:WARNING:backend_impl.cc(1779)] Destroying invalid entry.
[0224/132215:WARNING:backend_impl.cc(1779)] Destroying invalid entry.
[0224/132215:WARNING:backend_impl.cc(1779)] Destroying invalid entry.
[0224/132215:WARNING:backend_impl.cc(1779)] Destroying invalid entry.
[0224/132216:WARNING:backend_impl.cc(1779)] Destroying invalid entry.
Apparently the files have remained unchanged since February 24.