I had exactly the same thing. Turned out to be the connector between the crankshaft sensor and the rest of the wiring loom. It just needed unplugging and cleaning up.
Without it the ECU didn't know that the engine was turning over and didn't trigger any sparks. On my bike the connector lives on the left hand side just below the bottom coolant hose.
[Edited on 10-3-2005 by Jools]