What is UTXO and its erros mean?

I have some coinbase money that got stuck on my mining pool server. Now I can’t get it out!

Maybe I am using the wrong commands? I have many coinbase rewards that I can spend - I am mining about 10 blocks per day.

This is what I am doing:

zcash-cli listunspent:

[
{
“txid” : “91b7355ef4e41d498c19b23ab6c2c1e29dc176dc9695a0b560c52c409a95c809”,
“vout” : 0,
“address” : “t1M1Vndd7VcdeYhCe4kda3gXcvKuPX6Esqc”,
“account” : “”,
“scriptPubKey” : “76a9142266837fa82cf188ef470c619211b376ab7b8fca88ac”,
“amount” : 12.49875000,
“confirmations” : 598,
“spendable” : true
},
{

command:

zcash-cli z_sendmany “t1M1Vndd7VcdeYhCe4kda3gXcvKuPX6Esqc” “[{"amount": 12.49865000, "address": "zcbsFkFvPtCprCB9hQR7Kr9grHDVfCkeQb5o7ASQ4TKPQyqyLoQ6oMeYXftdHPf7GDz7vb9YkiPYF16vDNkUywj7MW4h4M9"}]”

opid-93b7ce0c-fd3b-44c9-891a-bd56354cf8b1

rolfversluis@pool:~$ zcash-cli z_getoperationresult
[
{
“id” : “opid-93b7ce0c-fd3b-44c9-891a-bd56354cf8b1”,
“status” : “failed”,
“creation_time” : 1486626134,
“error” : {
“code” : -1,
“message” : “general exception: std::bad_alloc”
},
“method” : “z_sendmany”,
“params” : {
“fromaddress” : “t1M1Vndd7VcdeYhCe4kda3gXcvKuPX6Esqc”,
“amounts” : [
{
“amount” : 12.49865000,
“address” : “zcbsFkFvPtCprCB9hQR7Kr9grHDVfCkeQb5o7ASQ4TKPQyqyLoQ6oMeYXftdHPf7GDz7vb9YkiPYF16vDNkUywj7MW4h4M9”
}
],
“minconf” : 1,
“fee” : 0.00010000
}
}
]