Thank you very much for your answer,
I tried, but pattern could not follow my path...
At the link above you can download my simple scene test...
1. Made a spline
2. Made a sphere
3. Placed the sphere at the beginning of the spline
4. Selected the sphere and used the move tool (with bent arrow tool on the right to select the spline)
5. ctrl+drag to place a copy of the sphere at the end of the spline
6. Selected a sphere of the pattern and changed the number of the object of the pattern.
Result: stright pattern and not a pattern that flows along the spline! Where was the problem?