Anyway, the real Fall of Empires comes from Coruption. Some of you have called it in-fighting but really its corruption.
Corruption allowed the barbarians to invade and conquer. The Eastern Roman Empire set out to reconquer the West but then Plague hit and wipped out over half the population.
If you can find me continuous documented money trails to all border garrisons with the attached command to open the gates for barbarians, and then explain why it took 600 years for Rome to fall, how it came that the Empire came into existance and expanded despite corruption and why it held its borders at some times, we might be able to discuss your "theory".
Infighting is not the same as corruption. You are welcome to back that claim up but as it stands, it is as substantiated as the claim that Rome fell because of a conjunction of planets or lead poisoning. Infighting had been going on since early Republican days, and in fact even led to the Res Publica Romana with the dethroning of Tarquinius Superbus.
Some people here have mentioned looking at the tools and knowledge they had. The ancients probably had even more knowledge but when barbarians invade they like to kill for fun and loot.
More knowledge than who? The other ancients? In which field, and what were the consequences based on which primary sources?

How do you know that barbarians like to kill for fun? That seems to be a tautology stemming directly from your interpretation of the term barbarian. You do know that Roman, Persian, Greek or Egyptian armies could and would kill and loot on a much larger basis, do you?
Who do they kill? - the rich.
And the poor. And sometimes the ones inbetween. "The rich" - I said it is a very simplistic theory - tend to get away much easier than any slave, subsistence farmer or the Roman plebs.
And who are the rich? - Educated. Then plague comes around, takes out portions of the population and pretty soon you have rich people scrounging for nessesicties and only teaching their children the basics instead of the advanced stuff.
Thats when the dark ages come.
Because everyone has forgotten how to make candles and cannot find the door's hut for lack of a compass, sure.
The notion that "the rich" are identical with teachers and doctors or that a plague would wipe out their private higher education system, or that a decline in the knowledge of Greek theatre and literature led to the fall is preposterous. And that is if I understand your sequence right. Are you saying that first the rich corrupted someone else who then did not guard the border, then the rich all died during loots, then the plague killed the commoners, and then the already dead or diminished rich could not teach their children how to heal smallpox or build an aquaeduct anymore (activities which Senators, consularii or the nobiltas in general did not indulge in much to start with)? I do admit to have some trouble making sense of this eclectic line of reasoning.
Look at the knowledge that currently defines our modern civilization. Electricity, Engineering, Medicine. The higher up you go the more education and training is needed to build and maintain modern civilization.
What does that have to do with the Roman Empire?
You get a plague and then a great war all of a sudden the doctors and engineers are in short supply. You get a bunch of successive wars and plagues over a generation then the teachers have all died and the rest are back to basics.
Anway, I'm rambling.
Pretty much sums it up I'm afraid. Could you elucidate a bit more why teachers die at a higher rate in wars against Barbarians, why these teachers are "the rich", and why a prior plague - when the doctors which had no clue how to heal it anyways were still alive - has been brought about by corruption and a decline of education?
Corruption was a big factor to the collapse of the roman west. In many ways the "barbarians" were more true to roman iideas than the romans in the end. Also, the were less cruel in many aspects. Rome never really developed anything, maybe modified what the learned from others but not really developing. It was the greeks and others in thne east that developed and reseaarched. Heck, the celts did more of that too before the romans went after the druids.
Why was corruption any factor? Who corrupted whom, and what exactly did they pay for? Who took the bribes, and what did he do in turn? The nobiles, and especially the municipal and regional euergetes certainly did a lot for a flourishing civitas than they did harm.
I'm not sure what precisely you mean with "Roman ideas" when you carry on to say that Romans did not have any ideas of their own. Or did you mean to write "ideals"?
There is a very fine line between invention and modification, and it is often too fine for a human eye or brain to perceive. It could even be argued that adoption is innovative. But anyways, from whom did the Romans adopt system of water transport, the Druids? Who did they turn to for the cohort legion? From which peoples did they copy their Republican levy system, or their Imperial administration? What technology did the Greeks invent during the Dominate, for example?
Judging by the comparatively slow pace of developments and the inherent high limits of any pre-industrial society, I do not think it matters a bit who invented and who adopted stuff in this era for the question of what led to Rome's fall.