To be a little be more precise.
msgs are defined this way
<f:loadBundle basename="messages" var="msgs"/>
Any help is highly appreciated
f:loadBundle in JSF 1.1 is not a JSF component at all. It just loads the data into the request scope. As soon as each next request has its own request scope, the f:loadBundle is useless.
a4j:loadBundle is created to serve this problem. Use it instead.
P.S. with JSF 1.2 and facelets, you can have more options.