This probably should not work here, but try setting BSA Redirection in OBMM > Utilities (sidebar) > Archive Invalidation. If you do not have OBMM:
1) Install it: http://tesivpositive.animolious.com/index.php?page=obmm
2) Learn how to create OMODs with it: http://tesivpositive.animolious.com/index.php?page=omod_installation
3) Make an OMOD out of the original downloaded archive of Seph's animation replacer by using 'Add archive'
Also, make sure your game is patched to the latest version. That is not relevant in this case, but it will be in the future.
What OS are you running?
Edit: New users guide - http://tesivpositive.animolious.com/#new_users_guide