can't erase PIC16F84A

[stefki]

hi all,
I can't erase PIC16F84A, the chip was blank, I successfully programmed wit hex file,but Now I want to erase and reprogram it again.

The erase button won't work. Error writting program area.

What can be the problem ? I have soldered the five wires directly to the chip.

Datasheet
http://ww1.microchip.com/downloads/en/d ... 35007b.pdf

This is my connection to the pic