Thank you so much to all who replied. I have made the suggested changes 
and the code at the beginning of the ead file now looks like this:

<?xml version="1.0" encoding="utf-8" standalone="no"?>
<?xml-stylesheet type="text/xsl" 
<!DOCTYPE ead PUBLIC "+//ISBN 1-931666-00-8//DTD ead.dtd (Encoded Archival 
Description (EAD) Version 2002)//EN" "">

However, we have now run into a new problem. The trasnformation process is 
failing to convert the finding aid to HTML. It appears that the xsl 
stylesheet I am using is causing the problem this time. According to 
Oxygen Editor, the problematic code is this:

<xsl:stylesheet xmlns:xsl="" 
xmlns:saxon="" extension-element-prefixes="saxon" 
doctype-public="-//W3C//DTD HTML 4.0 Transitional//EN" version="1.1">

Specifically, it does not like the version-"1.1". The error report states 

Engine name: Saxon-PE
Severity: fatal
Description: Attribute @doctype-public is not allowed on element 

I had initially simply placed a space between the period and the second 
one (which made no sense to me, but it made the error go away in Oxygen). 
However, with or without this extra space, it won't complete the 
transformation scenario for me or IT on our web server. 

Does anyone know how I can fix this error? I can not seem to wrap my brain 
around it. Thank you for all the advice and support you have already 
given. I truly appreciate having this wonderful professional community to 
call upon.

Anna Kresmer