Oh, wow... I found the solution
More than a day looking at the code without finding any error and I find it now that I just published in the forum.
I do not delete the post in case it could be of help to some other forum user.
The problem is in the second "bindParam" to which I put an "e" of more. The code on the results page should look like this:
--
<?php
$rsMatriculas = new WA_MySQLi_RS("rsMatriculas",$conexion,1);
$rsMatriculas->setQuery("SELECT * FROM matriculas WHERE matriculas.matriculas LIKE ? OR -1 = ?");
$rsMatriculas->bindParam("text", "".$_GET['tmatricula'] ."", "-1"); //tmatricula
$rsMatriculas->bindParam("text", "".$_GET['tmatricula'] ."", "-1"); //tmatricula1
$rsMatriculas->execute();
?>
--
Thank you very much.