[Webtest] another javascript error

[Test BCN]

I've just started with webtest, and I could make some simple tests, but when
it comes to more deep tests, just trying to logon, I always bump onto
javascript errors,...

Is it because I don't know how it works, or because it's not supported? What
can I do?

It is saying that a function is not defined, but I can see it in the page.

JavaScript error loading page
http://www.laboris.net/Laborislogin.aspx?ReturnUrl=%2fCandidato%2fCandidato-AreaPersonal.aspx:
ReferenceError: "ValidarFormulario" is not defined. (onclick event for
HtmlButtonInput[<input name="btnEntrar_div_en" id="btnEntrar_div_en"
type="button" class="submit" style="width:55px;height:20px;cursor:pointer;"
value="Entrar"
onclick="EnabledRndButton(&apos;btnEntrar&apos;,false);if(!ValidarFormulario()){return
false;};__doPostBack(&apos;btnEntrar&apos;,&apos;&apos;);">]#1)
Location

C:\software\Laboris\tests\Usuario\loginUsuario.xml (line: 15)
Details javascript errorReferenceError: "ValidarFormulario" is not defined.
(onclick event for HtmlButtonInput[<input name="btnEntrar_div_en"
id="btnEntrar_div_en" type="button" class="submit"
style="width:55px;height:20px;cursor:pointer;" value="Entrar"
onclick="EnabledRndButton(&apos;btnEntrar&apos;,false);if(!ValidarFormulario()){return
false;};__doPostBack(&apos;btnEntrar&apos;,&apos;&apos;);">]#1)  line1
 javascript
sourcefunction () { [native code, arity=0] }  failing linefunction ()
{  javascript
call stackReferenceError: "ValidarFormulario" is not defined. (onclick event
for HtmlButtonInput[<input name="btnEntrar_div_en" id="btnEntrar_div_en"
type="button" class="submit" style="width:55px;height:20px;cursor:pointer;"
value="Entrar"
onclick="EnabledRndButton(&apos;btnEntrar&apos;,false);if(!ValidarFormulario()){return
false;};__doPostBack(&apos;btnEntrar&apos;,&apos;&apos;);">]#1) at (onclick
event for HtmlButtonInput[<input name="btnEntrar_div_en"
id="btnEntrar_div_en" type="button" class="submit"
style="width:55px;height:20px;cursor:pointer;" value="Entrar"
onclick="EnabledRndButton(&apos;btnEntrar&apos;,false);if(!ValidarFormulario()){return
false;};__doPostBack(&apos;btnEntrar&apos;,&apos;&apos;);">]:1)