FWIW, I was able to work around the issue by extracting the fmt.tld file from appserv-jstl.jar and placing it under the WEB-INF directory of my war file, then modifying web.xml and adding the following tags:
[code]
<jsp-config>
<taglib>
<taglib-uri>
http://java.sun.com/jstl/fmt</taglib-uri>
<taglib-location>/WEB-INF/fmt.tld</taglib-location>
</taglib>
</jsp-config>
[/code]
Now Glassfish finds the tld and it works properly.
I had been using core JSTL tags without having to add these tags to my web.xml, therefore I assume it shouldn't be necessary for the format tags either.
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