Hello Guys,
I've already send this message on the Nord forum and someone suggest that it's from Virus setting:
I'm in brainstorming with some Midi troubles between my Nord E4D and Access Virus TI Snow synth.
Well, I use the NE4D as master keyboard and passing the sounds thru the Input/output of the Snow. This give me the possibility to heard the goods samples of the Nord and evenly use the good FX section of the Virus.
The Midi output of the Nord change the programs of the Virus (via Midi Virus Input) and I can use the Virus sounds "alone" as well and all works perfectly in this worflow 
For many useful reasons, I want to change workflow for have alls controls from the Virus: If I select a Virus program (in Multi Mode), it must be able to change the Nord E4D program as well. The Midi output of the Virus is connected to the Midi Input of the NE4D (as well NE4D midi output to Virus midi in for have keyboard datas...); after setup alls parameters of the 2 machines (canal number, send/receive...) I can show the little red led blink on the NE4D when it receive the Virus sending program change but the program dont change himself 
Any idea about something I missing?
In advance, thanks for your precious returns
Kinds regards, Fred