Some comments:
In the web.config, there is a value for the "myURI"
I removed the lines where you convert the query parameters to an int, and then back to string.
I define the ReportParameter[] parameters = new ReportParameter[1];
and if it happens to be one of the "xxyyCertificado" or "xxyyConstancia" types, it gets redefined to [2] and adds the 2nd parameter and for every report, adds the first parameter just after that code block.