[earl@b2x2:~/.bitcoin]$ pywallet.py --datadir=./ --wallet=wallet.dat --dumpwallet | grep "$ADDRESS_VISIBLE_IN_BITCOIN_QT"
You probably are missing the error message.
Try just this.
$ pywallet.py --dumpwallet
And if the wallet is encrypted, you'll need to add --password=PASSWORD
Well that was strange. I deleted the old wallet and let the bitcoin-qt generate a new one, then created a few new addresses, re-run pywallet and finally got what i need. :-)
And yes, there's a message about 'ecdsa' but I dont think I need that feature:
'ecdsa' package is not installed, pywallet won't be able to sign/verify messages