1. Scrum implementation fails because the processes of Scrum are not followed closely enough.
2. Scrum implementation fails because the organization does not adapt Scrum to its own environment/culture/practices.
3. The processes of Scrum are not important; only the values in the Agile Manifesto matter.
Many enterprisey types miss one of the key components of agility which is to release early and often. To the degree that you don't do this, your process is not agile and bound to suffer the same sorts of problems that traditional, plan-driven processes have. It may be that this is a temporary condition as you are just getting used to things, but you need to start releasing soon (and regularly). Remember, working software is the primary measure of progress. Putting documents on sharepoints and other traditional waterfall practices are not releases.
