Just piccked up a copy of AC2 and was doing fine until Sequence 4, the 'See You There' mission.

I run along, get to the glowie marker with various time to spare and nothing happens. Time runs out and it makes me start again. Really frustrated now, watched/read some walkthrough items on it, I'm ending up where they do to get the complete mission message, but I get nothing. Looks like it's glitched/bugged out - so can't go any farther in the blasted game. Any ideas on how to get past this?

Running the PC version, by the by.