Hi there,
I setup a ptp with 2 rb411AH + 2r52nM + 2 zirok 60 dual-polarity.
Signal strength -41/-41 - CCQ 98%/98%
It works great, but if I plug my rb450g where the clientes log in, in the LOG shows that :
wlan1: lost connection not polled for too long
wlan1: established connection
wlan1: lost connection, extensive data lost

How can I fix it and what is it causing this problem?

check you RoS versions on both device and wireless settings.
It will be helphful to provide

your signal is too strong

-40 too strong
-60 good
-80 too weak

this document is helpful with wireless error logs:
http://wiki.mikrotik.com/wiki/Manual:Wi ... Debug_Logs

ok, but I fixed the problem. It was the power supply.