Quick Question

[Thracian 06]

To create a new folder to play a mod for BI 16 What files do I have to copy

[Ciaran]

Just copy the whole game folder, it´s like having it installed twice on your harddrive.
The data folder might (note the subjunctive here!) suffice, but then you´ll have to copy it to and fro, depending on what you want to play (the mod or plain BI).

[Bwian]

Or, alternatively, use JSGME!

You create a folder called 'MOD' in your RTW install, and just install the mod to the MOD folder. Then you can easily switch in and out the mod with no need to worry about messing anything up