suddenly got negative balance in nvc pool, -0.02349075

doesn't make sense to me:
84897    sigesang    2013-10-17 11:16:35    Credit    Confirmed (520)       47000    -1.09375854
84885    sigesang    2013-10-16 19:35:20    Credit    Confirmed (520)       48569    0.41756697
84869    sigesang    2013-10-14 00:04:19    Credit    Confirmed (520)       48045    0.65270082
84866    sigesang    2013-10-11 19:16:25    TXFee    Confirmed (n/a)    4c1da8aTjBECFnpZoKV1HT17yeUBKsmv6D    n/a    0.05000000
84865    sigesang    2013-10-11 19:16:25    Debit_MP    Confirmed (n/a)    4c1da8aTjBECFnpZoKV1HT17yeUBKsmv6D    n/a    5.05166528
84835    sigesang    2013-10-09 03:55:21    Credit    Confirmed (520)       47000    1.09375854
84824    sigesang    2013-10-07 07:45:21    Credit    Confirmed (520)       46549    2.91414820

why -1.09 there, the amount i got before for block 47000?

"Hi - for one of the block (47000) you received payouts twice - I removed those transactions as pool is not earning enough to cover this..."
so I can't trust the transaction log it seems, 47000 is 2x payout but it doesn't show? unless one check sum of all (if I can trust that)?