Sorry to hear you are running into this issue. Could you answer below queries -
1. Open MyEclipse Blue IDE, from menu options click on MyEclipse > Installation Summary > Installation Details and copy and paste the same here
2. Attach .log file located at [your workspace dir]/.metadata/.log, replicate the issue and attach file here
3. Please clarify, if you have set the WAS 7 JDK as the one supplied by WAS?
4. Attach a screenshot of Window > Preferences > MyEclipse > Servers > Websphere Blue Connectors > WebSphere 7
5. Are you behind firewall / proxy?