Many thanks. I decided to update to:
System OE: PLi-OE
Distro: openpli
Firmware version: 4.0
Driver date: 2.6.18-7.4-20111109-r7.0
Kernel version: 2.6.18
Gui version: 2015-12-09-(detached from f46f533)

and the EPG runs perfectly "out of the box"

Thanks again !
Art