Juergen Stark, a representative from Germany at the ECB, is rumored to be resigning because he is unhappy with the ECB's bond purchases. The ECB was modeled against the German Central Bank, the Bundesbank, which has strong inflation fighting credibility. The ECB will lose credibility if this is true.
If this is true the timing is very unfortunate. The countries are scheduled to vote in a few weeks on the EFSF. The situation is already volatile and by resigning before the votes it will make the situation even more volatile. Would it kill him to suck it up and wait a few more weeks before he resigns?
***Update: rumors confirmed to be true