Your namecoin sending wallet is at /home/jackjack/wallet.dat
Your bitcoin receiving wallet is in your default bitcoin directory (if not, use pywallet --datadir option)
0. Download
my pywallet fork and exit namecoind
1. In console 'cd /path/to/pywallet/'
2. Run './pywallet.py --dumpwallet' and find
{
"addr": "The Bitcoin Address you sent namecoins to",
"hexsec": "privatehexkey64characterslong",
"label": "",
"sec": "5xxxxxxx"
}
3. Run './pywallet.py --importprivkey "privatehexkey64characterslong" --importhex --namecoin --datadir /home/jackjack/' (if testnetcoins, replace --namecoin with --testnet)
4. Restart namecoind with the rescan flag
Your coins are now again in your Namecoin wallet, and you can even use that Bitcoin address as a Namecoin address
I hope this will help someone one day