Hi Bertrand!
Feel free to post your own question in french. Some of our best Enthusiats speak french. I said some of our "best". Not me! I took french for 5 years in high school and never passed french 2!
It sounds like your case is different from the case I mentioned above because I was running three DIFFERENT VI's.
LabVIEW only allows one copy of a VI in memory at a time. This is entirely based on the name of the VI. You may be able to adapt to this restriction by copying your VI as three distint names e.g. VI_1.vi VI_2.vi, VI_3.vi.
This is the easiest approach and will work provided your sub-VI's do not have any trouble being called by different "main" VI's.
If the simple "re-naming" works for you good!
If not, I suggest you po
st a new question and include a copy of your VI so we can look and advise.
I hope this helps,
Ben