Well, technically it isn't your money unless the payment you received and then used to wager with confirms.

And that's where the problem lies.

Blockchain.info has a good tool to help understand the details, and you get this from clicking the "enable" advanced (at the bottom):
 - https://blockchain.info/tx/d1d6f0e127d066d418f445a7463e10277ee86acd7513c539b8377dda2d7e449f

Then click on Output for the 24.09017 BTC amount on the left, which brings you to:
 - https://blockchain.info/tx-index/34253280/0

So when you placed that wager, whatever client you were using (Blockchain.info in your instance) assumed you have 24.09017 to wager with.   Unfortunately, you didn't.  Part of that 24.09017 BTC, the amount of 2.48699998 BTC came from 12Cf6nCcRtKERh9cQm3Z29c9MWvQuFSxvT.

Except that ended up being a double spend against you.   And thus the entire 24.09017 BTC coin that you had used to wager with was never yours to begin with.  That 2.48699998 BTC sent to you will never confirm (as it has since been spent elsewhere).

So your wager using that money too will never confirm, and thus you aren't owed anything from SatoshiDICE because their payouts clearly only confirm when the wager confirms as well.

----

There are two ways this can be solved going forward.  

One way would be for SatoshiDICE to NEVER send payouts unless they are only using funds that have first confirmed.   That would require SatoshiDICE to either maintain a bigger hotwallet to accommodate payouts or to hold off on payouts when funds are running low to wait for other people's wagers confirm before using them to pay out the winners.

But that would require SatoshiDICE to change their backend system.

The other solution is for you to NEVER place a wager unless the funds you are using to wager have first confirmed.   Blockchain.info is more lenient than the Bitcoin.org client or the SatoshiRoller client  -- both of which require one confirmation before letting you spend the funds.  So you are using a client that is susceptible to this situation happening again and again -- and it does nothing to warn you that you are spending funds that haven't confirmed.

So your choices are, use a client that only will spend funds that have at least one confirmation (like, perhaps the new SatoshiRoller app, available for testing now) or accept that not every wager you make will be a valid wager (for the reason, you are trying to spend funds that might not actually be yours.)

Without knowing the exact details I cannot be certain but am most likely accurate in summing up your scenario with fewer words:

You never had 41 BTC of CONFIRMED funds.  You made wagers using UNCONFIRMED funds that may have increased the balance that shows, but that balance can't be trusted because it includes UNCONFIRMED funds.  

Or using even fewer words:

Don't count your chickens until they've hatched.

You have 29 BTC not 41 BTC.

Perhaps the initial payout was a transaction that never confirmed (due to including coins that had a double spend) but every win (and every loss) that is made with a wager that confirms eventually gets a payout that confirms as well.

If you receive a payout that ends up never confirming, a replacement payout is sent.  That is provable for every single SatoshiDICE wager that confirms -- going all the way back to April when they started taking wagers (though I'm not sure when the last independent verification of this has been performed).

It would be preferable if SatoshiDICE were to never send out payments with unconfirmed funds.   But occasionally they do and it each time it ends in a mess like this because people made wagers using coins that ended up becoming invalid due to prior double spends.  It would also be preferable if the SatoshiDICE page on Blockchain.info/wallet were to let you know when you are making a wager that uses funds that have not confirmed.  That way you would know not to count on a wager that shows a win as actually being a win until your wager actually confirms.

[Edit: The My Transactions list in Blockchain.info/wallet shows each transaction made even if it was made through the SatoshiDICE page.  You can see each transaction there and use that transaction id at SatoshiDICE to see what ended up happening.]

Please could you post your bitcoin address. It is possible some SatoshiDICE payouts may still be pending (https://bitcointalk.org/index.php?topic=77870.msg1358596#msg1358596 - https://bitcointalk.org/index.php?topic=127961.0)