Í've just seen many reports of 0.7 nodes getting stuck around block 225430, due to running out of lock entries in the BDB database. 0.8 nodes do not seem to have a problem.
2013-03-12 00:00:10 SetBestChain: new best=000000000000015aab28064a4c521d6a5325ff6e251e8ca2edfdfe6cb5bf832c height=225439 work=853779625563004076992 tx=14269257 date=2013-03-11 23:49:08
you're likely stuck. Check debug.log and db.log (look for 'Lock table is out of available lock entries').
If this is a widespread problem, it is an emergency. We risk having (several) forked chains with smaller blocks, which are accepted by 0.7 nodes. Can people contact pool operators to see which fork they are on? Blockexplorer and
blockchain.info seem to be stuck as well.
Immediate solution is upgrading to 0.8, or manually setting the number of lock objects higher in your database. I'll follow up with more concrete instructions.
If you're unsure, please stop processing transactions.
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Pieter