java.lang.NullPointerException PrincipalValidator

windu failed with error

Caused by: java.lang.NullPointerException

  at com.ptc.windchill.org.PrincipalValidator.isPrincipalInLDAP(PrincipalValidator.java:476)

  at com.ptc.windchill.org.PrincipalValidator.checkPrincipalJndiAdaptersLinkages(PrincipalValidator.java:437)

  at com.ptc.windchill.org.PrincipalValidator.runDiagnostics(PrincipalValidator.java:136)

  ... 29 more