Same issue here in Austin, TX. Error IDs 1:536, 1:6399, and 2:12. Issues limited to GT5; PSN checks out fine, no network issues on my end. Started 60-90 minutes ago, after having been working fine. Have deleted GT5 cache, restarted game, rebooted PS3, and tried the launch GT5 while signed out of PSN, all to no avail.
Seems pretty clear it's a PD server issue. I wonder what the geographic scope is? It looks like we have 3 US reports and one from Portugal, so it may not be limited to North America.
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Patience is a virtue. Sadly, it's one I lack. :-/