I'm playing as the Crusader states. When I end my turn on turn 64, the game will crash once Poland's turn comes around, specifically after he moves his ship. Here is the error log.

Spoiler Alert, click show to read: 
09:59:31.968 [system.rpt] [always] CPU: SSE2
09:59:31.968 [system.rpt] [always] ==== system log start, build date: Aug 3 2007 version bld-medieval2-kingdoms-104 (45562) ===
09:59:32.078 [system.io] [always] mounted pack packs/data_0.pack
09:59:32.125 [system.io] [always] mounted pack packs/data_1.pack
09:59:32.171 [system.io] [always] mounted pack packs/data_2.pack
09:59:32.218 [system.io] [always] mounted pack packs/data_3.pack
09:59:32.281 [system.io] [always] mounted pack packs/data_4.pack
09:59:32.296 [system.io] [always] mounted pack packs/localized.pack
10:01:42.031 [system.rpt] [error] Medieval 2: Total War encountered an unspecified error and will now exit.



I'm running Stainless Steel 6.4. Thank you for any help you can provide.