Sneak Preview 6.30 => J2EE does not start

Installing the 6.30 sneak preview on my WinXP (Media Edition) PC. JDK installed is 1.3.1_09. During SAP installation, I received a warning message: "Error, CJS-20024 J2EE engine JC00 of SAP system C11 didn't come up after 600 seconds: giving up". Also 'retry' did not fix this. I could 'ignore' and continue, but (as expected) then later I was not able to start the J2EE engine. .... Has anybody seen this, and would have an idea what to do?