money from thin air

my mom wanted to mine some of the .5eth block reward blocks, so i team viewed into her computer & installed alethzero, made her a fresh account, and let it start downloading blocks --- haven't mined anything yet, but she has 2048.9 finney

extremely weird --- decided to try to send a tx to my computer for a few hundred finney:

 i  20:12:01|main  New transaction ee56e0fd…{[CREATE]/0$47+21000@10000000000000<-b291451f… #0}
  X  20:12:01|eth  Sending from non-existant account. How did it pay!?!
  i  20:12:01|eth  #ee56e0fd… Dropping invalid transaction: State.cpp(977): Throw in function void __thiscall dev::eth::State::subBalance(class dev::FixedHash<20>,class boost::multiprecision::number<struct boost::multiprecision::backends::cpp_int_backend<0,0,1,0,class std::allocator<unsigned long> >,1>)
Dynamic exception type: class boost::exception_detail::clone_impl<struct dev::eth::NotEnoughCash>
std::exception::what: Unknown exception

Her rig still shows that she has 1500 finney (obviously some sort of bug here)