There is no easy way currently to run salvagewallet  on a secondary wallet .If you have a wallet-reset.dat backup, try using that one instead. If not try these steps below.

1) Shutdown client
2) rename wallet.dat to noloadwallet.dat
3) rename wallet-reset.dat to wallet.dat
4) Startclient with -salvagewallet
5) Be patient, after fixing keys, it will rescan 5million blocks, this can take a fair amount of time. Possibly hours depending on your computer.
6) After complete, shutdown client
7) rename your wallet.dat (previously wallet-reset.dat) back to wallet-reset.dat
rename your noloadwallet.dat to wallet.dat
9) start client up
10) do more frequent wallet backups!

You can alway monitor that progress by looking at the debug.log file.

I will work on adding an extra switch to salvagewallet to work on a secondary wallet For version 1.6.

Edit: If you are good with startups switches you can also also do this to save time.
1) Shutdown client
2) Create new dir called C:\hbn_fix
3) copy wallet-reset.dat to c:\hbn_fix\wallet.dat
4) startup client with -salavgewallet -datadir=c:\hbn_fix
5) After client is done and wallet is working, shut it down.
6) rename your wallet-reset.dat in your normal datadir %appdata% to brokewallet-reset.dat
7) Copy your wallet.dat form c:\hbn_fix to your normal datadir as wallet-reset.dat

This method may save a bit of time.