nero freezes while burning

Hi,
i am using NERO ULTRA EDITION 6. i tried burn some of my wmv files. first i converted this wmv to dvd format using WINAVI CONVERTER. then i tried to burn this dvd video format files. but nero freezes after 1%. i don’t know what’s wrong with this. i used TEON DVD -R.if anybody know how to solve this please let me know.
Thanks in advance