SOLVED: Was running bitmonero on 32-bit Ubuntu. Fixed when changing OS to 64 bit.
EDIT: Initial post indicated this was a UPnP issue, which it likely is not. I've updated the post below to what I now think is the problem.
I am trying to set up a Monero node (compiled from source Sept 7th). The blockchain seems to have been only partially synced. In my bitmonerod log this is repeating non-stop:
IN EDIT: Update log file excerpt below after running at log level 3.
2015-Sep-11 22:12:58.154735 BlockchainLMDB::open
2015-Sep-11 22:12:58.155122 BlockchainLMDB::need_resize
2015-Sep-11 22:12:58.155257 DB map size: 1073741824
2015-Sep-11 22:12:58.155391 Space used: 967413760
2015-Sep-11 22:12:58.155522 Space remaining: 106328064
2015-Sep-11 22:12:58.155650 Size threshold: 0
2015-Sep-11 22:12:58.155811 Percent used: 0.9010 Percent threshold: 0.8000
2015-Sep-11 22:12:58.156804 Threshold met (percent-based)
2015-Sep-11 22:12:58.156940 LMDB memory map needs resized, doing that now.
2015-Sep-11 22:12:58.157083 BlockchainLMDB::do_resize
2015-Sep-11 22:12:58.157331 LMDB Mapsize increased. Old: 1024MiB, New: 2048MiB
bitmonerod then silently exits after this, and restarted by supervisor. Nothing else shows up in the logs.