Hello.

I'm using CC2430 Coordinator and Routers, and have ZStack-1.4.3-1.2.1 installed (I'm not using ZigBee pro).
I burn this Zstack's firmware into the Router and Coordinator, which comprises the application I wrote.

I'll describe the problem please.
The Router was sending 9 big packets to the Coordinator, with 2 sec space between each packet.
Each Packet contained 150 bytes, but the Router sent each packet in two 75-bytes sub packets.

So actually it went like this:

75-bytes sub-packet.
200ms space.
75-bytes sub-packet.
2 sec space.

... (x7)

75-bytes sub-packet.
200ms space.
75-bytes sub-packet.
2 sec space.

After that, the Router stopped responding to Coordinator, and only after I power-reset the Router, it responded again.

Why is this happening please?

Thank you very much.

Could anyone help me please?

Your best bet is to post your question over at the TI forums. They have a lot more people familiar with Z-Stack over there.