Several JDWP commands require that a thread be suspended but do not specify an error code if the thread is not suspended:
MonitorInfo
Frames
FrameCount
OwnedMonitors
OwnedMonitorsStackDepthInfo
Also, these commands
ForceEarlyReturn
PopFrames
require a thread to be suspended, but the error code returned if a thread is not suspended is
THREAD_NOT_SUSPENDED 13 If the specified thread has not been suspended by an event.
If the thread is suspended by a non-event, eg, a suspend command, either the
description of the command is wrong, or the error code is wrong.