Macro issues

I’ve been reading these forums for quite some time now. This is my first time to post and I was wondering if anyone with more knowledge could test out this macro and see if you can figure out why it tends to lock up. Thanks for any help/advice.

/console Sound_EnableSFX 0
#showtooltip Frostbolt
/castsequence reset=target/combat/5 Frost Bomb,null
/castsequence reset=target/combat/5 Presence of Mind,Mirror Image,Icy Veins
/castsequence reset=5 Frostbolt,Frostbolt,Frostbolt,Ice Lance,Ice Lance,Frost Bomb
/castsequence [mod:shift]Frostfire Bolt
/script UIErrorsFrame:Hide();
/console Sound_EnableSFX 1