FCXxxx526I Not in SEND state, command stacked

Explanation
A command has been entered for transmission to the server machine, but we
are currently in receive state, waiting for the result of a previous command
to be returned first. The new command has been stacked and will be transmitted
when the previous command's output has arrived.

System action
The new command is stacked for later execution.

User response
Wait until the previous command's output has arrived.