Try it unloaded, remove your transistor circuits, check the output with a scope. Are all the bus signals correct ? Is the device reset properly ?

For obvious reasons, your code would be better as:
ORG 0000
JMP 100H

ORG 100H
Start: ;etc etc.


Write a tight loop addressing the 8255

Lptst: MOV @DPTR,A
JMP lptst

Check you can see WR and CS on the chip.



Steve