Bugzilla search portlet fails when using MSSQL database

A user reports the the Bugzilla ID search portlet fails when using SQL Server:

javax.servlet.ServletException: SQL Exception while executing the
following:SELECT ID, groupid, FIELDTYPE, FIELD, OLDVALUE, OLDSTRING,
NEWVALUE, NEWSTRING FROM changeitem WHERE FIELD=? AND OLDSTRING=? ORDER
BY groupid desc (The text, ntext, and image data types cannot be
compared or sorted, except when using IS NULL or LIKE operator.)
at
org.apache.jasper.runtime.PageContextImpl.doHandlePageException(PageCont
extImpl.java:867)
at
org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContex
tImpl.java:800)
at
org.apache.jsp.bugzillasearch_jsp._jspService(bugzillasearch_jsp.java:86
)
at
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
at
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.ja
va:311)
at
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
at
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Applica
tionFilterChain.java:284)
at
....