thank you Dave,
sure that i'm wrong in something (I or my PC..)

In the attached snapshot there is the behaviour that I can get using the following procedure:
- got the sample txt and edited by Notepad
- asterisks are comments
- used two columns and spaces (one for time, the other for force)

I attach the file and the snopshot for the behaviour.

Please confirm it is correct that the first lines are blanked (i think not)?