Can you tell us the output you get from the execution of both systems ?
In the QEMU Send show the follow output:
Pok kernel initialized
Send value 0
rtl8029: PCI init failed!
[*]
rtl8029_read: error: ring buffer 257 overflow!
[RTL8029] SEND DATA THROUGH NETWORK FROM LOCAL PORT 3 TO GLOBAL_PORT 13, size=0
rtl8029_read: error: ring buffer 257 overflow!
rtl8029_read: error: ring buffer 257 overflow!
Send value 1
.
.
In the QEMU Receive show the follow output:
Pok kernel initialized
Receive value 0
rtl8029: PCI init failed!
[*]
rtl8029_read: error: ring buffer 257 overflow!
[RTL8029] READ DATA FROM LOCAL PORT 4 TO GLOBAL_PORT 13, size=4
rtl8029_read: error: empty read ring buffer 4!
rtl8029_read: error: ring buffer 257 overflow!
rtl8029_read: error: ring buffer 257 overflow!
Receive value 0
.
.
Also, can you tell us which version of QEMU are you using ?
QEMU emulator version 0.14.1 (qemu-kvm-0.14.1)