I don't know much about AC3D, but it might be exporting the texture paths with their entire path intact eg. 'C:\textures\wood\dark\wood.gif' instead of just 'wood.gif'.
Look for an option to turn texture paths on/off or something similar. If all else fails, open the file in a text or hex editor and remove the path before the texture name by deleting it and re-saving the file. :)
Look for an option to turn texture paths on/off or something similar. If all else fails, open the file in a text or hex editor and remove the path before the texture name by deleting it and re-saving the file. :)