Did you try pressing U or P on the keyboard? Did you get as close to it as possible and have Manny face it? Did you try pressing E to see if Manny notices it (sometimes his head movements can be a bit subtle)?
If you're absolutly frustrated and don't feel like working it out here, the saved files for year two can be found here
but be warned, I don't know which one takes place after you pick up the gold flakes, so you should at least try the first listed saved file for year two and try to pick it up there again, you might have better luck on a different file