The latest file has been saved in the wrong format.It's .fmf and should be.tac.That's the issue.
I will continue using the original tactic though because it owns
I will continue using the original tactic though because it owns

In order to use this tactic in FM you have to follow these steps:
1) Copy this file into this folder Documents\Sports Interactive\Football Manager 2015\tactics
2) In game click on the arrow under the tactics screen -> Manage Tactics -> Import
3) Select this file from the list and click ok
4) Now it should appear in the list with the tactics you can use in game.