Problem with metarouter

Hi, Im working with 450g (routeros V4.2) and openwrt as metarouter, I install the dude on the board to, but every 5 to 10 minutes the router is rebooted by the watchdog. I change the power source by my laptop ibm (18,5V and 3.5A) but steel rebooting. Can somebody help me??? Thank

look here:
http://forum.mikrotik.com/t/rb450g-openwrt-metarouter-strange-problem/32210/1