Bonjour Tom,
To copy a material from one object to another you have 3 choices:
1- Open the Explorer, find the material you want to copy, and d&d it with Ctrl on the other object. This should create a copy of the material on the other object.
2- Select your objects, and hit Group. This will create a group. In the Explorer, select the group and put a material. The material will be carried to all members of the group.
3- Open your material ppg, and hit Save. You will be prompted to save your material on disk. Now, apply a material to another object. Open the material's ppg, and click Load, and load the material file you just created (.preset file).
To copy a material in another scene, the best way is to use #3 above.
Hope this helps
Salutations - Cheers
Bernard Lebel