Shuddering

[xurbanx]

Had a problem at work just a few hours ago.
Started up the car during work and noticed the exhaust sounded a bit different (think the Wrx's exhaust - kinda like a shuddering noise), as I drove away the engine light came on and that prompted me to pull over.

Then a few minutes later I gave it another drive (engine light still on) and this time, the shudder from the exhaust was still there plus if I stepped on the gas, the whole car would shudder uncontrollably.

Popped up the bonnet with the engine running and you could hear a faint "whine" emitting.

Would anyone know what caused this? Or what's wrong?