Are you running the latest wallet release?
v0. 8.6.5
v0.8.6.4-Patch 0 Alpha for Mac. Downloaded it from the ANN today, so it's most recent version. Does .4 not work correctly with this block chain?
It definitely works past that block, but the dev changed some things with timestamps in regard to velocity in v0.8.6.3 and above so that may be the issue you are running into.
I would try to use v0.8.6.2 to get past that block (let it go several blocks just to be sure) and then you should be good to go with the current version.
I'll let the dev know of this issue in slack and hopefully with the next update he'll add a fix.