Help me..shogun throne bug!

[caravel]

Been getting back into Shogun lately and started a Shimazu/hard/sengoku campaign, conquered half of the map, turtling, and have wittled the rival factions down to just the Takeda and Useugi. Noticed a bug last night I've never seen before. It may be that my install is corrupted, but I sent two emissaries to bribe a rebel army. The first emissary succeeded so I wanted to cancel the second emissary's mission. I picked up the emissary and dropped him which is how I usually stop agent missions, and at that instant the game crashed to desktop. Pity I hadn't saved for quite a while...