This is an SL animation bug. The cuffs v 2.2.x onwards avoids this bug. Just go to the Update Switch and update.

If you still get this error, IM Lulu Ludovico.

Old information follows:

This might happen due to one of the following:

• You just updated your Signature Cuffs, did a setup, transferred your stats from the old HUD, but forgot to activate your plugins.  
  
• Your arm/thigh cuff activation did not complete successfully.
• The activation completed successfully but you were disconnected from SL, or crashed soon after. The SL asset server is not properly updated with your HUD state.
• The activation completed successfully but you detached the HUD before receiving the "Safe to Detach" message.

 

• You logged off soon after a successful activation.

   
    FIX: If you get the animation error message, it can be fixed by re-activating the plugin. Simply wear the plugin Activator, and when asked, select "Re-activate". Addendum: because this is an SL bug, you might still occasionally get this error.