Bug#548128: Similar Problem
On Friday 11 December 2009, Mikko Eley wrote:
> web server trick worked a charm syslog is attatched. Thanks for the tip
> I didn't know debian could do that.
No problem. Next time please gzip large files before sending them though
(otherwise you run the risk we never see them because our mailing list
rejects the mail).
The log shows a bunch of probably related problems.
The first is the huge number of messages 'implausibly old time stamp
1904-01-01' while installing packages.
It is possible that the wrong system date/time is the cause of the
"untrusted packages" error because GPG needs a reasonable system time.
So, first question is: is the hardware clock of your system set correctly?
But normally at least the system time should get updated  during the
installation. However, that fails here:
kernel: [ 197.895382] warning: process `rdate' used the deprecated sysctl
system call with 1.40.
clock-setup: rdate: Could not set time of day: Invalid argument
And that looks to be the issue described in this bug report:
So, to solve the installation failure you will need to set your hardware
clock to a reasonable date, assuming your systems BIOS/firmware allows you
to do that. You can then retry a full installation.
If that does not work there is another workaround, and that is to boot the
installer with the option 'debian-installer/allow_unauthenticated=true'.
But it really would be better to have the clock set correctly (assuming
that is the cause of the GPG failure).
 The hardware clock should also get updated, but only at the very end of
the installation and I've no idea whether that actually works on powerpc.