I had a new wordpress theme working fine on a dev server and then I put it on the live server. I uploaded it via ftp, but I can’t get it to show in the wordpress admin > appearance > themes. I don’t even get an error message about a broken theme. I checked and made sure that the style.css was in the theme folder. I logged out and back into the worpdress admin, but it still won’t show. What are the other things to look for?
Did you try to add the theme through the Dashboard !?
Try to Deactive all Plugins then Install the new Theme.
Be sure that there is the Good URL on your Theme… Space or Something Like that…
If you have WordPress properly installed, you will have a “themes folder”. Check to see if you uploaded your theme to this folder.
Make sure you uploaded it to wp-content/themes/yourtheme, not wp-content/themes/yourtheme/yourtheme.
You could also try zipping the theme file and uploading it directly through your dashboard. 
Just to make sure - does the style.css have the wordpress theme declaration? without that a theme wont be detected by wordpress.
I believe that it is a yes to all of your questions/suggestions. I really think that it is a hosting issue. I had the theme working fine on my hosting.
Not really. Because for some reason if the theme file has not uploaded correctly even then you might have the issue. Hence, best is try to reinstall the theme and check.
Also check file/folder permissions. I am not sure that wordpress will even look in a folder it can’t read.