Okay, if the name and the directory (109e4_1) shows up but the skin displayed is the default, that means it's not in 8-bit format.
If you don't have a file it reads the default (that's why instruments and all the other stuff still read as default). If the file is not 8-bit (256 color) then it can't read it, and it thinks "it's not here, I need to use the default", and you get the default displayed.
If the 109e4.txt (a.k.a. the object.txt file, generic term for aircraft description file) is visible offline, and if the directory is visible in the skins viewer, but neither shows the proper skin, it means they ARE reading it, just not the bitmaps. Right click on the 109e4-1.bmp file and select "properties."
You should be on the "General" tab. Go to the "Summary" tab. If the tab has greyed out boxes hit the "advanced" button. You need the white screen with the summary information. Once there check "bit depth". It needs to be 8.
If it's not 8 it's often 24 or 32 bit.
You need to do the following when exporting:
1) save your work up to this point
2) flatten the layers (in photoshop Layer > Flatten layers
3a OR 3b
3a) use the program itself to change to 256 colors. Image > Mode > Indexed Color (in photoshop, you want to work in RGB mode but export in indexed mode). Choose Adaptive palette, 8-bit or type in 256 colors. I like diffusion dither with best quality, if I go this way. Hit okay. File > Save As > choose bitmap in the drop box, give it a name, and when it asks which format to save it in 8bit should be the only option available.
3b) use a plugin to export to 256 colors. File > Export > Bright. Give it the proper name as the plugin often adds a funny symbol instead of the name.
why flatten first? Sometimes plugins flatten the image themselves and screw up the way it looks. I found this out several times with bright plugin. This is especially true when you get complex layers interacting with each other. Flatten using photoshop first, then the plugin doesn't screw it up.
EDIT:
Oh, and DON'T save the file after you flatten it. Depending on your program you might be able to undo this step. You can continue working from there. If you save the FLATTENED file over the layered file (they still have the same name!!!) you lose all your work.