thats not it works, what you did there was bind "l" to execute the comand "laser". you should follow what the other post say THOROUGHLY.
just so you know what you are doing, here's a brief explanation on how the binds work and what you need to do get the laser bind working.
first, binds are just a shorcut to execute one or more of the game's engine comands
second, the server has its own comands, they are only executable trough the chat.
third, you can either create all your binds trough the console, or by creating a .cfg file which you can edit anytime you want. the later is ideal if you plan on having 20+ binds
so, what you need to do is bind a key to sayin the chat the server's comand that gives you the laser, its goes like this:
sm_ is the source/game engine comand that says something in the game chat whithout it actualy apearing in it, you need to add what you want it to say
!laser is the server's chat comand that you use during the game to get the laser
so what you need to do is this:
bind "l" "sm_!laser"
hope that helps you understand how it works!