Have you got JRE from a reliable source like: http://ccm.net/download/download-101-java-runtime-environment.
It's not necessary to launch Java to gain access to open office once it is there. As a matter of fact, Java control launch should be deactivated.
OpenOffice should detect this installation and let you choose it for use in OpenOffice via the Tools-> OpenOffice.org -> Java. If you have a JRE installed that is not detected, you should be able to add it through this same menu.
You can install a JRE or configure OpenOffice to use Java at any time to get missing functionality to work.
From the OpenOffice main menu use: Tools -> OpenOffice.org -> Java, and uncheck "Use a Java runtime environment". However, Open Office recommends that you have a Java Runtime Environment on your system to take full advantage of OpenOffice's features without any issues.