Who does the "technical project manager" report to in your organization? Any project manager, regardless whether he's technical or business, will ultimately report to business.
But, what is business? Well, this is where it becomes a bit confusing: business can be the program manager, it can be the IT department, or it can be the company's top executives.
So, if the PM reports to the IT department, he's technically reporting to technology, but his reports will be elevated eventually to business. It all depends on the standard communications plan setup by your PMO.
In all fairness, I think that the hierarchy and the structure in your organization are good - but it's very important that both the business project manager and the technical project manager keep each other in the loop, because business always affect technology, and vice versa.