Error 0x88781204

Value: -2005396988 | 0x88781204 | 2289570308

What does it mean ?

DMUS_E_ALREADY_SENT  
The DMUS_PMSG has already been sent to the performance object via IDirectMusicPerformance::SendPMsg().
Value: 4612 | 0x1204 | 0b0001001000000100

Where does it come from ?

FACILITY_DIRECTMUSIC  
Direct Music (part of DirectX) - Audio
Value: 2168 | 0x878 | 0b100001111000

StackOverflow

Other Errors for FACILITY_DIRECTMUSIC