MIM_LONGERROR

Sent by a MIDI input driver to a client application when an invalid MIDI system-exclusive event is received.

DWORD dwParam1
Specifies a pointer to a MIDIHDR structure identifying the buffer containing the invalid data.
DWORD dwParam2
Specifies the time that the data was received by the input device driver. The time stamp is specified in milliseconds, beginning at zero when the driver received the MIDM_START message.