It is possible to write a label with the simbol %?
If I write this the label session shows me a message saying something like "The height of the label must be greater than (due to simbol %)"


Thank you in advance,

Yes, use %% in your label.

Try %%.
Standard labels already exist for it:
For example:
in tc: tcgen.perc1
in td: tcgen.percentage

Thank you it works fine.