supress disable audio for macro to cast spell

[i214chess]

Any tips on how to disable error sound for specific macro? Combat log will display (and I also hear error sound): `You fail to cast Fireball: No target.`. I bind hotkey to mouse scroll wheel up.

Here is a video, do you hear the clicking? the other casting noise too? https://streamable.com/3kkou

Code: Select all

/console Sound_EnableSFX 0
/script if GetUnitName("target")==nil then TargetNearestEnemy() end
/cast Fireball
/console Sound_EnableSFX 1
/script UIErrorsFrame:Clear();

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UPDATE: http://www.evernote.com/l/AM8aGOXoH45OYqwDG7UrfR17SydQofnGyG0/