Those aren't "arms" exports, at least not what is considered "arms". Most of our "defence exports" are low ticket items, components etc. For example, HAL sells Sukhoi-30's components to Malaysia and other operators. I
rkut has subcontracted the manufacture of several parts to HAL (including the canards, stabilizers and fins). Besides, HAL also exports spares (and performs maintenance) for all the aircrafts mentioned here:
Hindustan Aeronautics Limited - Exports - Spares & Services
Now these are some of the items that ASSOCHAM considers as "defence related exports", but are not classified as arms transfers by SIPRI. And selling subcomponents does not really make it an arms exporter. That term is reserved for a company or nation that exports complete weapon systems. (Dhruv is one such successful export item for HAL.)
Similarly many companies, public and private, export a lot of subcomponents and subsystems. All these put together amount to 2 billion dollars worth of exports. But most of these are not "arms exports". It would be difficult for Indian industries to export arms, because the needs of the Indian armed forces itself is so huge, that satisfying the orders from them would itself take a lot of time. Akash and Brahmos are two missile systems that are successful enough to be exported to many countries. But our industry cannot even keep up with the demand of our own forces.