Yahoo!'s metric is EPS (ttm), meaning the Earnings per Share over the trailing twelve months. The EPS that you're calculating is not the over trailing twelve months, rather it comes from the 10K covering the 12 months ending Aug 31, 2011.
Adding EPSs together from the 4 most recent quarters yields an EPS of 2.11, which is pretty close to the Yahoo figure. Keep in mind this is less accurate than a 10K figure, because on a 10K the shares outstanding figure will be more accurate. The shares outstanding figure can change throughout the year, if the company issues new shares (like in a split, or as a part of management compensation).
The difference in EPS of $0.01 is possibly attributable to the company rounding each EPS to the nearest cent, while Yahoo! calculates it's own EPS, saving any rounding until the end.