Shoot.
Run cmd Start > Run > type
cmd
//press Enter
switch to the drive that you have FS2 installed on
type
C:
//press Enter (replace "C" with the letter you have FS2 installed to, eg "D")
change to your fs2 dir
type
cd \games\freespace2
//Press Enter (replace \games\freespace2 with the correct directory if necessary)
type
dir /on /s>%homepath%\Desktop\FSdirlist.txt
Press enter. you should now have a text file on your desktop with the file listing of FS2 and all subdirs, with sizes. Attach that file here. When you post, click "Additional Options" on the bottom (if you don't see it, press the "Preview" button first), then browse to your desktop and attach the file.
This way, we can make sure the problem is not a corrupted file... if it's not, then I guess the other thread mentioned here is prolly your problem, I'm not sure (but BtRL uses 3.6.9, so

if one works, the other should too, this is why I suspect a corrupted file brought on by multiple disconnects from the Internet while using Turey's installer... my siggy links to a DVD you can download instead, but you already did the work for Turey's method, might as well stick it out. If it isn't easily fixable, you might want to try hip63's DVD, it is compatible with Turey's Installer.)