I can help (just solved it):
1. I'll presume that the theme "filblack3d" is saved in your "C:/unzipped" folder (probably under the file name of "Pack-fiblack3d[1]")
2. Open up your FTP program
3. In your FTP program, open up the "Pack-fiblack3d[1]" file. Then open up the "fiblack3d" file. Next, open up the "themes" folder. Then, single click on the "fiblack3d" folder and transfer it into your "/themes" folder.
Hope this helps, let me know if you have any problems.
- Thomas