CAC1001
I'm sure that Communism would work fine if you could find Party bureaucrats that were totally non-corrupt and completely ethical, but those people are rare, and people that are really self-sacrificing tend not to get into positions of power...
Communism wouldn't work fine even if every member of the government had a heart of gold. Even if completely non-corrupt, no government can centrally coordinate an economy. What you would see, however, is a total lack of corruption within said centrally-planned system.
Remember, a market economy has millions of prices. Whenever one price changes, essentially all the other millions of prices must change in relation to that one price change. So you have millions of prices constantly fluctuating all in relation to one another. Trying to centrally calculate this is impossible.