Is there a way to convert old macros to work on 3.3.5?

This is a macro that I used on old vanilla servers for my Shaman:

/script if not buffed("Lightning Shield") then cast("Lightning Shield") else local hasMainHandEnchant, mainHandExpiration = GetWeaponEnchantInfo(); if (not hasMainHandEnchant or mainHandExpiration<61000) then cast("Flametongue Weapon") end end

It used to be an all-in-one buff button, it would check for lighting shield, cast it if wasn't present and do the same for weapon enchant, except it would also check if it was about to expire (less than 61 seconds). I tried to use it on 3.3.5 servers but I get an error, anyway I can use something similar?

I don't think that's possible on wotlk in a macro. You would need an addon for that. And it would only work correctly while you are not in combat. Blizzard has limited such automation in spell casting.