Still having problems.

   "difficulty" : 43742.95218211,
    "search-interval" : 16,
    "weight" : 98.24037299,
    "netstakeweight" : 541828.10622686,
    "expectedtime" : 307566

This is a relatively modest balance, but I'm starting to become concerned about the length of time since I last staked. As I write this message, it has been 2014621 seconds (over 23 days) since my client last minted a block. According to the above estimate, I should mint a block in about 3.5 days.

Each time I check, the client is using zero CPU, and does not seem to be trying to stake.

reservebalance is set to false (amount=0)

I upgraded to the latest version a couple of days ago, but behaviour has not changed.

Any ideas?