The error indicates that IS server not yet started,that is the reason you are getting ConnectException when you are trying to login developer.
If you are running IS server on local machine it may take a while or several minutes to initialize startup.
In this case start the IS using commandline this will be helpful to debug whether IS is started or not.
<wm_installdir>IntegrationServer/bin/server.bat -debug 4 -log server.log
HTH,
#Integration-Server-and-ESB#B2B-Integration#webMethods