I received a similar message even though I had Java downloaded. I finally got the solution, and the problem was with java, not with mplus. It turned out that some miscommunication between my registry cleaning software (RegCure Pro) and my antivirus software (Norton 360) prevented the computer from recognizing that java was present, even after I had ensured that java was activated in every place possible (java control panel, IE browser options, Chrome browser options).
The solution that ended up working was to (1) uninstall every version of java from the control panel; (2) re-run the registry cleaning program; (3) restart the computer; (4) re-install java. After I did all that, the diagrammer in mplus is working just fine.
Ian Koh posted on Wednesday, September 25, 2013 - 9:45 pm
I have a 64-bit version of Mplus 7 and I've just installed a 64-bit version of Java (the most recent one). Yet, I still get an error message about Mplus needing the most recent version of Java to run Diagrammer. What can I do to resolve this?