White Stripe Just Below Where Sleeve Ends

Could you please share your package file and your blend file? I can't tell from the pictures (which aren't loading here) what the cause would be.

I'm very sorry but I don't know what is causing the issue.
I can see that you have a lot of seams on your mesh that need smoothing out using the Remove Doubles option though. You may also need to Split Edges on some parts of the cuffs around the arms.
When you are in blender, switch to Solid shading and you will be able to see all of the seams that need fixing straight away.

Sorry. I'm not always the best at explaining.
I noticed in Studio that there are dark shadows down the side of the outfit that don't look smooth.



If you go into blender and set the shading to Solid Shading then these seams are very easy to see.



They basically run all around the sides of your mesh where the front and back meet. You need to select these vertices and use the Remove Doubles option on them. This will smooth out the join and make the shading fade out correctly.

For the cuffs it was the part I have lined in red here:



The game is currently trying to make it look smoothed but there should be a hard edge there since the fabric is rolled up against the arm. To fix this one you select the edges that you want to be crisp and sharp and then use the Edge Split option from the Mesh menu on the bottom of the screen.

Let me know if I still haven't explained well enough and I will try again.

Hi. It is caused by cut numbers.
The number of meshes your package file has is important and so are the cut numbers they have. For some reason my s4s does not find get famous content, so i cannot see how many s4studio_mesh_ does the dress you used as a base have, so I'll use the skirt as an example.
As you see, the count start from the bottom. Lower calfs have 0000, upper - 0001, skirt - 0002 ( I assume this is how the game can tell whether to put boots on top of pants or underneath )

In your package lower calfs have 0002, upper - 0001, which means these cut numbers are already redistributed in a wrong way.
I changed them accordingly, then combined the dress and arms into one mesh ( Shift-select meshes and hit Ctrl J ), gave it 002 cut, saved, and used different dress as a base for a package ( that has 3 s4studio_mesh_). It fixed it.
Also, there is a noticeable split ( orange ) where two meshes were combined around collar. You can remove it by selecting vertices along it and removing doubles. There are also "shadows" ( white ) around sharp edges. You can remove them by selecting said edges and splitting them ( Crtl E - Edge split )

Wait, what exactly do you have open? Your package or the original dress you started your package from?
Actually let's start from a basic game dress, or it might not appear in the game of people who do not own Get Famous ( if you intend on sharing it ).
- open your .blend file and combine s4studio_mesh_1, s4studio_mesh_2, s4studio_mesh_3, s4studio_mesh_4 by Shift-selecting them and pressing Ctrl J. Change cut of this new mesh to 0002.
- select upper calves ( s4studio_mesh_6 ) and change cut to 0001;
- select lower calves ( s4studio_mesh_5 ) and change cut to 0000;
- split edges and remove doubles as explained earlier if you want. Save;
- start a new package from this dress;

- import your blend file. This shadow will disappear