Some things will cause windower to crash. One of the main causes is updates to FFXI breaking plugins and Windower.
After a patch, if your game crashes on load, please check the Windower News Forum for news from us.
Disable any broken plugin until it is fixed.
A few things are known to cause windower to crash
IR Devices - Please disable IR devices before using Windower. ~TODO~ someone link to a guide here.
XFire - You can not use XFire with Windower & FFXI
STeam - You can not launch Windower with Steam
WindowsBlinds/AlienWare Skinning (Any 3rd Party windows skinning) - These will crash FFXI - Use uxtheme.dll hack or disable pol.exe from being skinned.
ProcessGuard - Will likely cause problems with windower - Thats what processguard is designed to do, stop windower from doing what it does.