Another issue we now saw several times during the installation of IBM Connections 4 (both times a medium deployment option has been choosen):
If you want to generate the plugin for the IBM HTTP server you might see the Websphere Deployment Manager crashing with a Java "out of memory" error. To avoid that you should increase the maximum Java Heapsize for the Deployment manager process to 1024 before generating the plugin. You can do that in the Integrated System Console -> System Administration -> Deployment Manager -> Java and Process Management -> Process definition ->Java Virtual Machine -> Maximum heap size)
In the installation wiki only the Java heap size for the application servers are mentioned, but no information is give that you should increase the size for the DMgr as well.