copy the ipk file to tmp and by telnet

opkg update && opkg install -force-overwrite /tmp/*.ipk

Download links:
oe1.6 and openpli2.1
http://www.tunisia-dreambox.info/dre....6_3.4_all.ipk

OE2.0 and openpli 3.0 images
http://www.tunisia-dreambox.info/dre....0_3.4_all.ipk