After upgrading IBM Connections 5.0 to 5.0 CR2 and upgrading the FileNet Content Navigator you see the error “CIWEB2039 – The AccePlugin plug-in contains errors” if you try to load the ACCE (Filenet Admin Console). To resolve that, add the following line to the HTTPD.CONF of your web server(s) and restart the web server(s):
SetEnvIf Request_URI ^/acce(.*) no-gzip dont-vary
You might also need to clear your browser cache. Afterwards the ACCE should load successfully again.