I have resolved the load balancer plugin issue for web server 7.0/7.0 u1. The issue is caused by 4 dll libraries that is present in web server 6.1 but not available in 7.0. It seems that 7.0 is using a newer version for some of the libraries. I copied the missing files from web server 6.1 to 7.0 and the load balancer plugin is able to load balance the cluster on glassfish 41a.
So, glassfish v2 will work with web server 7.0/7.0u1 in addition to the supported 6.1. Great!
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