I recently installed the latest Nifskope on my pc. But when I load a mesh from the game or a mod, it appears all white. There is no texture on the object.

I have a windows 7/ 64 bit pc

You have to set folder for it to seek textures.

Render>Settings>Rendering

Make sure you spellout possible tree structure.Mine is
E:\Games\Morrowind\Data Files\Textures
E:\Games\Morrowind\Data Files
E:\Games\Morrowind

and make sure 'look for alternatives' is checked.

I have this habit of extracting new mods onto new folder on desktop. Then I add new foldertree right at top where the mod textures are. Makes mod testing easier for texture.