Looks like something is blocking access to 127.0.0.1 - maybe as a result of the 901 installation - and thus XPages cannot connect to the built-in local web container.
If you do not have an http proxy set, can you check two more things?
a) Is this line “com.ibm.collaboration.realtime.webapi/startWebContainer=false” present in the following file (it is by default, I believe). It is set to false so that other components do not start the web container too early.
\framework\rcp\plugin_customization.ini
b) Also can you open this file (\workspace.config\rcpinstall.properties) and look for a couple of entries and let me know what they are set to - if present:
-Dcom.ibm.pvc.webcontainer.ssl.configfile
-Dcom.ibm.pvc.webcontainer.port