hmm lets see:

you are trying to use PORTA whithout disabling the analog parts
you have the wrong osc settings so the leds will flash after 0.5 light years and not seconds and seem to be always on
you have the wrong osc settings so the leds will flash after 0.5 us and not seconds and seem to be always on
you have managed to setup the tris registers incorrectly even your code is "correct"

Your HW is connected in some weird way

The programmer has managed to write an incorrect hex file to your PIC

The pic has watchdog activated and is contantly resetting before reaching 0.5 s

It is really hard to tell without knowing what pic, your schematic and of course the code and configuration bits.

Anyone else who feel like taking a wild guess??