I also found that it resets itself.Could it be the perfboard problem?.

I just made SPI work between 2 PIC ( 18F452 & 18F458 ).It worked but sometimes,it resets and return to main loop although i had set BOR to lowest and make PWT enable + placed 2 npo 7 multilayer ceramic and 2 tantalum cap as near as possible to PIC.The Vreg uses LDO with good quiecent current which i belive would handle load very well.So why sometimes it resets itself?