You have to think in terms what is different from Local version vs Server version.
Seems to be your custom theme is the issue on the server
I bet you are missing some files on your server, or they need read/write permissions.
FireBug is your friend.
That will tell you exactly what your issue is.
Post the link to your website here and someone can look at it for you.
I find the best thing to do is the following:
- Use Web Deploy if you can
- If using FTP don't upload file by file, instead zip it and only ftp the zip folder.
- Then unzip on server
When having issue I find dong the following can help:
- Stop your application pool
- ReStart it
Check for issues
If that does not work then delete everything on server and reupload.
I find those steps the fastest way to get things working server side.