It is worth noting that Andrew Wiles' initial proof of Fermat's Last Theorem also had a bug. This was later fixed, with help. From http://en.wikipedia.org/wiki

It is worth noting that Andrew Wiles' initial proof of Fermat's Last Theorem also had a bug. This was later fixed, with help. From http://en.wikipedia.org/wiki/Fermat%27s_Last_Theorem http://en.wikipedia.org/wiki/Fermat%27s_Last_Theorem : However, it soon became apparent that Wiles's initial proof was incorrect. A critical portion of the proof contained an error in a bound on the order of a particular group. The error was caught by several mathematicians refereeing Wiles's manuscript.[112] including Katz, who alerted Wiles on 23 August 1993.[113] Wiles and his former student Richard Taylor spent almost a year trying to repair the proof, without success.[114] On 19 September 1994, Wiles had a flash of insight...