Hi, Jaime,
did you also request a license code from ESTWSIM after you have installed the program?
This is a procedure where you create a data set with this program and send it to ESTWSIM by e-mail. Then you get back a data set with the license-key to activate the the full version of the program.
The link below gives you an illustrated description of this procedure.
http://www.estwsim.de/lizensierung.pdf
Kind regards
Peter