Moved to bug reports.
Edit: Check the ini-file, block "[Midi Library]". For some reason it's doesn't always seem to save those paths as absolute paths, so for example moving the program from a drive to another may cause the MIDI import fail to map instruments (confirmed with a test case).
I just checked it and they were mapped to H:\windows\.... I never have had windows on an H: drive. Weird. Corrected this to C now.
Now it loads fine.
"Heh, maybe I should've joined the compo only because it would've meant I wouldn't have had to worry about a damn EQ or compressor for a change. " - Atlantis
"yes.. I think in this case it was wishful thinking: MPT is makng my life hard so it must be wrong" - Rewbs