If you take the term company in context of the period, it seems very similar to what we would consider a corporation today.  'Royal charter' sounds a lot like 'registration', given to a 'company' (the company you keep), to form a body to do business, business which usually involved a government sanctioned monopoly.  It could be argued that corporations go back at least a 1000 years when using this type of analysis.  The City of London Corporation (which some could argue is one of the centers of financial power in the world, especially today) claims  to have existed in one form or another prior to its first recorded charter in 1067, and is recognized as such.  So when he (Ifo Ikeda) refers to an 800 year old corporation, I believe he is only applying todays terminology to old world practices which he sees in todays world.  On the other hand he may just have mis-spoken and meant 400 years, describing the East India Company specifically.  But the observation that the Incorporated City of London became what is now a dominant institution in the world of finance (housing both the legal and financial centers of the western world) is certainly important in the context of the Occupy Movement, and I believe that is what he is refering to.

When he refers to decolonization, i don't believe he is refering to living human beings (but you'd have to ask the author, and I suggest you do that), I believe he was refering to corporate colonialism.   To attempt to de-colonize any of the worlds counties would certainly be impossible.  But to give back freedoms to people which have been stolen under corporations (governments are corporations) is well within the grasp of a united, informed group of human beings. 

I have to stop here, work calls in about 5 minutes.