Roger,
I would encourage you to install Sun’s JDK from their site (1.4.2_08) and change your environment PATH to include it’s bin directory, also adjust your Eclipse shortcut to include the -vm argument pointing at the Sun JDK:
eclipse.exe -vm c:\j2sdk1.4.2_08\bin\javaw.exe
Using the JRE or JDK that ships with an app server as your runtime VM is never a good idea, a lot of these companies (especially IBM) instrument the JREs or JDKs that may cause problems for other software.
You may also want to check your JUnit run task to set it to use a different JRE to run with (not the BEA one) and see if that works.