Office 2007 issue when opening files

When i try to open a word or Power point, after 10 seconds i got:
However, if I try to open it few seconds after, it works...anyway how big is the file...
Desactivating my antivirus (NOD32) changes nothing..
As you can find on some forums, i made again the file extension association (by the way, it's hidden in <> through the control panel)..no way...

Repairing office 2007 didn't do the trick
Any clue folks ?