It might be because you can't pass through a player variable, so %uuid of player% literally has no mean because their is no "player" in the option, just make a variable instead of using an option

 

Code (Text):

1.  
2. on swap hand items:
3.     set Cooldown1 to {dashCD::%uuid of event-player%}
4.     cancel event
5.     if {Dash::%player's uuid%} > 0:
6.       set {_u} to {_p}'s uuid
7.       if {dash.last1::%{_u}%} is set:
8.       set {_wait1} to difference between {dash.last1::%{_u}%} and now
9.     else:
10.       set {_wait1} to {@Cooldown1}
11.        if {_wait1} >= {@Cooldown1}:
12.          set {dash.last1::%{_u}%} to now
13.          set player's walking speed to player's walking speed * 5
14.          wait 15 seconds
15.          set player's walking speed to player's walking speed / 5
16.       else:
17.          send action bar "&cYou need to wait %difference between {_wait1} and {@Cooldown1}%" to player
18.  

pretty sure there's tiny mistakes with indents with that i wrote, but this should help you.

options can be set for general things like permissions, messages, etc, but for variables, you can't really use options for it, options is more for the code rather than the game, the code doesn't recognize the player via code, only via the game itself, so once it loads, it'll recognize what it is supposed to recognize.