In cubase sx, I suddenly can't write to a midi track. I'm able to play the instruments, but when a midi track is armed and recording the resulting track is blank, just a funny short "chord" at the beginning that I didn't play. As track is going along in record, it flashes with every key press, but doesn't write anything.

Everything else ok. Simple setup.

Powerbook G4 1.5 GHZ. I just installed OSX 10.4.4 update and reinstalled my (newly certified) Firewire 410 drivers. Haven't changed anything else. Ran permissions repair.