Got the game.
The problem I experienced is a crash to desk top when selecting map options. It can occur when selecting any number of map options - not just the oceans options. It doesn't occur immeadiately. You can select some map options though it's unlikely that you'd make it through the entire list. Starting from the top and selecting items from most options, I most frequently generated the crash at 'Continent Placement'. I have not noticed this problem in any other script.
I have no idea what's going wrong with the script. No python errors are generated that I can see or am informed of. If anyone has any ideas, I'd be grateful to hear them.
The script is capable of generating maps. The problem arises in the custom game menu, not beyond it.
For those that consistently use the same settings, there is a way to get around the crash:
Go into your CivIV or Warlords folder (depending on which version you used before BtS) and copy the file 'LandMasses.cfg'. Paste this file in the Beyond the Sword folder, copying over any file of that name which already exists. This file contains the options which were selected the last time you generated a map using LandMasses in Vanilla or Warlords. Selecting LandMasses in BtS will use these options as default.
Alternatively if no 'LandMasses.cfg' file exists in either the CivIV or Warlords folders then generating maps in either of these games will produce one though, since this requires changing discs, that seems like a lot of trouble.
Alternatively, again, generate a series of very small (so that the loading times are as short as possible) LandMasses maps in BtS, changing a few settings at a time. Each generated map will update the newly generated 'LandMasses.cfg' file so that eventually the default will be the prefered setting.
If you don't use the same settings consistently, but keep most of the options the same, then using any of the above should still be fine. In my experience the game allows you to make some changes to the map options before it crashes.