When the application failed to get online/offline property of MIDI device, this error will occur.
It may be a bug of the application.
I made MIDITrail Ver.1.2.0 F70109 for Mac OS X (temporary fix).
Please download following file and try it out.
http://miditrail.sourceforge.jp/release/MIDITrail-Ver.1.2.0-F70109-MacOSX.zip
http://miditrail.sourceforge.jp/release/MIDITrail-Ver.1.2.0-F70109-MacOSX_src.zip
Could you tell me the name of your MIDI devices?
I want see the capture image of MIDI studio window.
How to open MIDI studio window
1. Launch "Audio MIDI Setup".
2. Click "Window" -> "Show MIDI window"
Reply to #70109