your macro is whacked out.

[s]/castsequence [target=focustarget, nochanneling: mind flay] reset=combat vampiric embrace, mind flay, mind flay, mind flay, mind flay[/s]

this needs to be something like

/castsequence reset=combat [target=focustarget] vampiric embrace, mind flay, mind flay, mind flay, mind flay