2 CRM 4.0 on-premise servers to same database using NLB and not plugins working

I have recently added an additional server with CRM installed to a configuration that contained a CRM server and a SQL database server. Per the installation guide, I was instructed to setup a NLB to handle traffic to the 2 CRM servers and add the NLB to the MSCRM_CONFIG database. I have successfully setup the new CRM server, configured the NLB for the 2 server, and updated MSCRM_CONFIG with the NLB but when applied updates to record via the UI for the new CRM server I am getting "unable to load plugin assembly" errors. 

What additional step(s) do I need to perform to resolve this error and have all existing plugin to trigger as expected?  

My Setup:
NLB  --> CRM server 1    --> SQL server

         --> CRM server 2