"not yet recovered"?

Hey guys, does anyone have experience with the mysterious message, "Spell failed (not yet recovered)"? I'm trying to do a /click tanking sequence with my DK, as recommended here and there, but it's breaking on plenty of spells with the "not yet recovered" error in the combat log. I always get it on Blood Boil and Death Coil if I try to do them as part of the /click sequence, and see it now and then on Blood Strike as well. I don't understand the problem; mob's alive, check ... plenty of runes and runic energy, check.

Is it a weird lag issue? A problem with /click sequences in general? Any ideas?

I'm guessing they're still on cooldown.

So you need to insert additional commas into those sequences.

Experiment at a target dummy.
Add commas to things which try to fire off, but are not yet ready.
Remove commas from things which are ready to cast but not used for a while.
Tweak until you're happy with it.