I have checked your TxID on
http://ltc.blockr.io/ and
https://chain.so/LTC and
https://block-explorer.com and couldn't find it. So your wallet hasn't broadcast the transaction to the network successfully yet.
Try to use getrawtransaction and then push it to your peers with sendrawtransaction.
BTW, you should post this in the altcoin section.
Could you gimme a link or s.th. which explains this
getrawtransaction and
sendrawtransaction? I dunno what's this and how to use it.
If a moderator joins this thread, please move it to the altcoin-section. Thanks.
Help-> Debug window-> console-> "there you can type "help" and see a list of available commands"
Maybe it says that you are trying to send a duplicate transaction because that one is already in your client, in that case, maybe you need to dump the private key of the address "or addresses" holding your ltc before the transaction and then impot them with a new wallet.dat file
*edit: maybe your problem is that you sent the transaction before it synced and you had a displayed balance with more funds in it than you really have... because seems you are trying to send 12.5 when you already had sent 3 and your total incoming transactions are 12.5ltc... and seems there is another outgoing transaction under the purple rectangle border
