Well, that at least tells us the *right* package is getting loaded, so its evidently some kind of reference problem. I sent you a PM with info where to send your file.
EDIT: OK, I've looked at your mesh file. And here's the good news: your mesh is being loaded! The bad news: you have to start over. There are a few problems with what you've done:
1. From the looks of things, it appears that you are using a version of SimPE newer than 0.35c. Versions newer than 0.35c will not work with Brianna's tutorial. Your Y and Z axes are inverted. You'll see that your mesh does appear in body shop but that it's sprawled out over the floor (it's aligned along the wrong axis). That's something that results from using a newer version of the mesh importer. I'm not positive if you used Delphy/Miche's import tool, or if you used the one in SimPE but it looks like the one in SimPE to me, however. You can futz with the importer's axis orientation in SimPE on the plug-in tab - but this is moot since we don't want to be using the plugin's importer or exporter here.
2. Second, the other reason I say this is that you're also missing all of your bone references (which is sort of important if you want your sim to ever animate
You can tell this if you load your mesh in body shop and the sim's arms are all outstretched instead of at their side. You can also tell by looking at the Joints tab in Milkshape and finding it to be empty. The import/export facility in SimPE doesn't know how to handle bones and can only be used on non-boned meshes.
3. You're also missing your body morphs (fat, pregnant, etc.) which again suggests this. When you look at the Groups tab in Milkeshape, you should see "BODY" and "BODYMOD.1" and "BODYMOD.2", etc.
4. You also have a very hard seam along the side of the sim that runs the full length of the body. This means your surface normals are not being interpolated properly. Another artifact of the "old tools".
So here's what I am going to suggest. Throw out Brianna's tutorial for a moment and do the following instead:
1. Download and install Wes_H's Body Chop Plugin-In for Milkshape v3.02 (I assume you're using Milkshape here) (available at MTS2 in the meshing forums)
2. Go back to the original Sims03.package file and re-extract your original mesh. But when you do this, right click on the mesh in the file listing and choose "Extract" (NOT the Extract button on the GMDC plugin!). The file will be saved as a .5gd.
3. Fire up Milkeshape, choose File | Import | TS2 Body Chop Importer V3.02. When it asks you if you want to import groups, say YES.
4. The first time you do this, your mesh is going to look like ass and there will be lots of blue lines going everywhere. You need to scale your joint sizes down. Go into File | Preferences | Misc and change Joint Size to 0.007500 or something thereabouts and click OK. You only need to ever do this once. Your blue lines should all condesnse into small blue spheres representing the model joints/bones.
5. For now, you want to hide all but the primary body morphs. You can edit these later if you so desire. Go to the Groups tab and select BODYMOD.X and HIDE them leaving only body and body_alpha visible.
6. Edit the mesh in Milkeshape as you did previously.
7. When you're finished, choose file Export | TS2 Body Chop Exporter V3.02 and save the file back out.
8. Now, using SimPE open your combined package file (the one you sent me). Right click on the GMDC in the file listing, and choose Replace (again, do not use the Import button on the Plug-In!!!) and replace it with the file you exported from Milkeshape. Your mesh is now imported.
SAVE (and make a backup!)
You *may* need to run Fix Integrity on your mesh file again. But before you do that, go and fire up body shop and see if its showing up now.
Let me know how that works. The above procedure may sound more involved, but once you do it one, you'll realize its actually more expedient than the procedure outlined in Brianna's tutorial - and the results are far better.
J
PS. One artifact you may or may not notice (depends on the mesh) is that a slight break may appear between the head and the neck of the body. This is an artifact of how Wes_H's plug in deals with bone weighting. The neck verts are weighted down just a little too heavily. If this happens to you, just go back into Milkshape, select the neck verticies, and nudge them up just a touch and resave/reimport.