Ok, now I understand why you were having problems
This particular skin uses a color fill option for the main area, instead of stretching a bitmap (like 99% of other skins), its also overly complicated by all the options
but this is what I had to do:
1. open the first file in the skin, find 'Variation3=102,
Windows 98"
This tells me that this variation has its own variables applied after everything in this '1' file is read (also what bitmap to use)
2. we go to 102 (2 files down) and note that Main_bitmap=102
3. export bitmap 102
4. realize that bitmap 102 doesnt have any gray to its right, and thus something funky is up
5. ??? (lets call it magic, because i really duno what i did possibly nothing, it took about 15 minutes)
6. change the Main_bitmap_slices_X in file 1, (changing the last number from 0 to 3
7. change Main_bitmap_slices_Y in file 1 (changing the first number to 3)
8. compile
9. add 6 pixels to the height, and 3 to the width (and then edit the colors of said pixels)
10. import the new image, save and exit and throw into .skins folder
.
Here is the finished product, (I think, not a big win98 buff so it might need a few more tweaks, though that should be alot easier now, that the bitmap actually stretches how its suposed to)
PS I broke every other variation except the windows 98 one
so if you want other versions from that skin, just save it with a new filename