Easy52 downloader

I make a easy52 downloader using with EZ31 program (design by Puiu). You can get more detail at :
" http://www.kmitl.ac.th/~kswichit/easy2puiu/easyp52.htm"
It erases, writes completly but verify error. Please give me some PALs can occur. Thank you very much indeed. (I try to connect with Puiu but no result.)

Have you checked the programming voltage? See if itss exactly 12V. If not try using 1% precision resistors for regulators.