Thanks for the quick reply.
The ";" symbol is no problem because I used this first time in my first XSN file and there it's working. It's strange that I reproduce almost the same thing and here doesn't working.
In my first XSN is used in a Repeating Table and here, in my new file, in Repeating Section.
Writing the formula in the Value of Action, after validating with OK the formula will be changed always from the "," to the ";". I have an EN-US version of InfoPath.
Sincerely,
Nagy Ferenc