There are to many possible issues.
Jan 2013 it was suggested not to use php 5.4X by sd.
So that could be one.
If you are using iso-8859 and your new database is using utf-8 another possibility of corruption. you could check using like phpmyadmin open your database and see what collation is used on the tables.
Mod security. This is just a guess but since you are on a vps you probably could disable it, if it is used to see if it resolves the issue.
I highly suggest you either open a support ticket for help or hire somebody to help. Meaning one of the expert users here like Gizmo or SD or call your host for assistance.
