(Spoiler: I am from the former communist block.)
EDIT: (I hope you don't mind if I reply to everyone here in my original comment.)
Philosophizing on what Marx meant by what he said is lot like Bible-reading study. It is nice to speculate on what God meant when he said "You must kill those who worship another god [Exodus 22:20]" but it is more important to know how those killing in His name understood it. In our context, one look at Syriza's economic programme should end all discussions on what Marx really meant with the "dictatorship of the proletariat". Raising wages, employing more people in the state sector, subventions, subsidies, free healthcare and education along with stiffening the labour market, nationalisation of industries and raising taxes up to 75%. That all obviously sponsored by new loans once they successfully ditch their current debt.
That brings us bak to my original point: there is not a single example of successful Marxist economy, regardless of what part of the Marxist wish-thinking you embrace.