I know this isn't pretty, but it would be relatively quick: I would suggest just manually going through the svn revisions for that file using a "human" binary search. If you have 2000 revisions to go through, you would only need to physically look at 12 revisions to narrow it down to the offending revision.
Let's say the line was added in r1000 and the latest revision is r3000. Then check r2000, if the line still exists there, pick a revision halfway between r2000 and r3000 (ie r2500), otherwise pick a revision halfway between r1000 and r2000 (ie r1500). Just continue using this manual search algorithm to narrow it down. With a window of 2000 revisions, you should get it within 12 iterations. (2000, 1000, 500, 250, 125, 64, 32, 16, 8 ,4, 2, 1, bingo!)