Re: How many orbiting satellites can be put up there?
It depends. If you want to put something on the equitorial geo-stationary belt, then yes, there is slot allocation. However this rocket wouldn't even manage to get itself anywhere near on a trajectory in that directdion, let alone a payload.
In Low-Earth Orbit, there is a generally agreed rule that if you put something up there, you have to make sure it comes back safetly and doesn't just litter. The new Metop sats had a problem with this, and the redesign to carry enough fuel to de-orbit safetly was significant. However Metops are also significantly bigger than this rocket can fly.
That leaves the little micro / nano satellites etc. I think that the rules generally depend on the launching country, and are generally more relaxed. You generally have to ensure that it will de-orbit within a certain time-frame, which normally just means putting it into the correct orbit. However, for example the law in the UK says something like if you want to launch something into space, then you have to get it up there and back by chauffeured Rolls Royce and jump though a few hoops on the way, while wrapped in red-tape.