I do not think that "подношу" and "в" are even compatible. I cannot think of any example. Maybe some oneelse could find any.
"Я подношу его в комнату" sounds clumsy.
There are two options:
"Я вношу его в комнату" - I carry it into the room. (So, you bring an object from the outer space to the space inside the room).
or
"Я подношу его к комнате" - I carry it towards the room. (I approach the room, but do not enter inside).