how does one map a transaction number to a block with just the bitcoind client?
figured it out after finding my own previous post about how I found out this info with americancoind, coin seems to have gone to a duplicate address, by its error message on attempting to resend the raw transaction. but bitcoind doesn't tell you what block it's in, merely stating error: {"code":-5,"message":"transaction already in block chain"}. however, on searching through the source (rpcrawtransaction.cpp) I noticed that getrawtransaction takes an extra arg, verbose, which if greater than 0 gives the blockhash:

jcomeau@aspire:~/rentacoder/jcomeau/bitcoin/src$ bitcoind getrawtransaction 3dd264f603f75871c5a36b61db8e137d8cee6b019a8d5bdfdabd7383ccc47068 1 | grep block
    "blockhash" : "000000000000000116f3abab7d0f620f620eae189de29ddb06fe8baae566467a",
    "blocktime" : 1393013064


and with the blockhash you can use getblock:

jcomeau@aspire:~/rentacoder/jcomeau/bitcoin/src$ bitcoind getblock 000000000000000116f3abab7d0f620f620eae189de29ddb06fe8baae566467a
{
    "hash" : "000000000000000116f3abab7d0f620f620eae189de29ddb06fe8baae566467a",
    "confirmations" : 255,
    "size" : 341358,
    "height" : 287092,
    "version" : 2,
    "merkleroot" : "d0fd6154ba64682b48c9c15600ee7c8594336cf4c0a2917b5cbcf1f5a74d2096",


so, 287092 is the block number that contains the transaction.