From: Oleksiy Stashok <Oleksiy.Stashok_at_Sun.COM>
Date: Mon, 19 Apr 2010 14:47:31 +0200

It could be due to limitation on number of keep-alive HTTP requests
made on a single TCP connection.
You can try to change the following settings in the domain.xml

<keep-alive max-connections="250" thread-count="1" timeout-in-
seconds="30"/>

instead of "250" - set "-1" for unlimited number of keep-alive requests.

Pls. let us know if it helped.

WBR,
Alexey.