[SethPDX]

Originally Posted by DG

Error charged if batter later reaches base. If not then no error.

It's an error regardless of how the AB turns out.

Originally Posted by Rich Ives

10.12 (a) The official scorer shall charge an error against any fielder:
(1) whose misplay (fumble, muff or wild throw) prolongs the time at bat of a batter, prolongs the presence on the bases of a runner or permits a runner to advance one or more bases, unless, in the judgment of the official scorer, such fielder deliberately permits a foul fly to fall safe with a runner on third base before two are out in order that the runner on third shall not score after the catch;