I know I already asked this before but I didn't have a chance to investigate further. I am trying to get my old wallet (xcoin) to sync so I can transfer my balance to new DarkCoin wallet
all you *should* have to do is drop your old wallet.dat file into the new Darkcoin wallet's .darkcoin folder (normally hidden inhome file in Ubuntu) or it's the darkcoin folder inUser/yourusername/AppData/Roaming/darkcoin in windows Vista, 7 and 8
*remove the old (newer) wallet.dat file first, don't merge. Just in case.*
If that doesn't work, something might be wrong with your old xcoin wallet.dat (which should be completely interchangeable with a darkcoind wallet.dat)
Interchangeable?
Yes, the wallet.dat is the key of the account. It is all you need to recreate your wallet. Just get a working wallet up and running, then go into the darkcoin folder (...\AppData\Roaming...) Delete the wallet.dat file in there (unless it's important, then save it somewhere else) and put in your old xcoin wallet.dat file. Remember shut down the wallet and do this without the wallet running. Then restart your wallet and your old xcoin/darkcoin should appear.
Note: if you used the File > Backup Wallet function, you may have named your wallet.dat something like Xcoin.dat. You will need to rename it wallet.dat if that is the case. Or you can just use ctrl+c ctrl+v the wallet if it's not running

Also, never try to backup your wallet.dat file by copying it from the darkcoin folder while the wallet is running. It might be corrupted (but won't show anything) If you want to save while the wallet is running, always use the File>Backup Wallet function.