Error with taglib parseDate

Hi all,

I use <parseDate> in webapp "www.buildtrees.com" as follows:

***	
	<fmt:parseDate var="birthdate" value="${param.birthdate}"
pattern="MMM-dd-yyyy" />
***

It works great when I visit the site with my computers.  On the other
hand, some of my web visitors produce the error below:

***
Exception: javax.servlet.jsp.JspException: In <parseDate>, value
attribute can not be parsed: "OCT-02-2002" 

Error message: In <parseDate>, value attribute can not be parsed:
"OCT-02-2002"
***

I suspect the problem is browser related.  Does anyone has a solution
for this?  I searched the internet, but I could not find anything that
could help, primarily because I have not been able to reproduce the
error with my computers.  I had to wait for a web surfer with the "wrong
configuration" to access the site.

All help appreciated.

Lamine