Going Javascript crazy...

I have several scripts generated by a RPG CGI program.  Script 1 and script 2 
below were generated in the same program loop.

The problem is that Script 1 throws an error:
"document.updTerms1.BEGDATE is either null or not an object".  This occurs 
regardless of what is in the field, so the browser must not be recognizing it 
as an object.  Script 2, which is identical for all practical purposes, works 
perfectly.  I've been over it and over it and I cannot figure out why one would 
work and not the other.

Here are the scripts and the accompanying forms

SCRIPT 1:
<script language="JavaScript">
<!--
function check1() {
if (document.updTerms1.BEGDATE.value == "" ) {
alert("Beginning Date cannot be blank.");
return false ;
}
else if (document.updTerms1.ENDDATE.value == "" ) {
alert("Ending Date cannot be blank.");
return false ;
}
else if (document.updTerms1.AMOUNT.value == "" ) {
alert("Amount cannot be blank.");
return false ;
}
else {
document.updTerms1.submit();
}
}
//-->
</script>

<form name="updTerms1" method="post" action="/members/SUPUPDTERM">
<input type="text" name="BEGDATE" value="11/1/2002" />
<input type="text" name="ENDDATE" value="10/30/2003" />
<input type="text" name="AMOUNT" value="65.00" />
<input type="button" value="Update" 
onClick="check1()" />
</form>


SCRIPT 2:

<script language="JavaScript">
<!--
function check2() {
if (document.updTerms2.BEGDATE.value == "" ) {
alert("Beginning Date cannot be blank.");
return false ;
}
else if (document.updTerms2.ENDDATE.value == "" ) {
alert("Ending Date cannot be blank.");
return false ;
}
else if (document.updTerms2.AMOUNT.value == "" ) {
alert("Amount cannot be blank.");
return false ;
}
else {
document.updTerms2.submit();
}
}
//-->
</script>

<form name="updTerms2" method="post" action="/members/SUPUPDTERM">
<input type="text" name="BEGDATE" value="1/23/2003" />
<input type="text" name="ENDDATE" value="12/31/2003" />
<input type="text" name="AMOUNT" value="12.00" />
<input type="button" value="Update" 
onClick="check2()" />
</form>

Any Javascript experts out there who can figure out what's happening?

Thanks,

Joel