buttonSetCaption to change based on user input variable

I am currently working on a form that spawns pages and adds the serial number to each page and changes the Button name to the serial number the technician types in.  It works the way I expected, but changing the buttonSetCaption command using a variable also generates an error.  This was liveable but the technicians have requested that we add a way to change the serial number within the document instead of having to create a whole new form. This has become problematic and I can not find a solution online or in any of the forums - any help/insight would be greatly appreciated. Here is the code I have so far:

// If button is Clicked and the hidden check box is not checked - the Analyzer1 check-off pages will be spawned;

var cb2 = this.getField("CB2").value;

// Assign Templates to be spawned a variable so they may be recalled;
var a1a = this.getTemplate("Analyzer1A");
var a1b = this.getTemplate("Analyzer1B");
var a1c = this.getTemplate("Analyzer1C");
var a1d = this.getTemplate("Analyzer1D");

if (cb2 !== "Yes"){

var resp1 = app.response({cQuestion:"Enter The Analyzer Serial Number.", cTitle:"H2S Analyzer Documentation", cLabel:"H2S Analyzer #:"});

if ((resp1 === null)||(resp1 ==="")){

this.getField("Anal1").ButtonSetCaption("Analyzer 1");
}
else{

a1a.spawn({nPage:this.numPages-1,bRename:false,bOverlay:false});
a1b.spawn({nPage:this.numPages-1,bRename:false,bOverlay:false});
a1c.spawn({nPage:this.numPages-1,bRename:false,bOverlay:false});
a1d.spawn({nPage:this.numPages-1,bRename:false,bOverlay:false});

this.getField("CB2").checkThisBox(0,true);

// buttonSetCaption placed at end due to error that stops code from running.  

this.getField("Anal1").buttonSetCaption(resp1).valueAsString;
}}

else{

var nser1 = app.alert ({cMsg:"Documentation For Analyzer 1 Has Already Been Created.\n\n" + "Do you wish to Change the Analyzer Serial Number?",nIcon:2,nType:2 });
// User Pressed Yes
if(nser1 === 4){
var nresp1 = app.response({cQuestion:"Enter The Analyzer Serial Number.", cTitle:"H2S Analyzer Documentation", cLabel:"H2S Analyzer #:"});
nresp1 = resp1;
this.getField("Anal1").buttonSetCaption(resp1).valueAsString;
}
}