Quote Originally Posted by DVX BELLORVM
You can't use ladders on the large stone walls, so the only useable solution is the sapping point.
Gah, I can never remember which walls which lol.

Anyway, the only solution is not to wait for M2TW [b]starkhorn[/b, Barbarian Invasion, as far as I'm aware, does not suffer from this bug. So yeah, buy BI to avoid the bug I guess...