####<Nov 13, 2009 11:58:23 AM CET> <Critical> <WebLogicServer> <machine-name> <as> <Main Thread> <<WLS Kernel>> <> <> <12
58109903043> <BEA-000386> <Server subsystem failed. Reason: java.lang.NumberFormatException: null
java.lang.NumberFormatException: null
        at java.lang.Integer.parseInt(Integer.java:415)
        at java.lang.Integer.parseInt(Integer.java:497)
        at weblogic.ldap.EmbeddedLDAP.validateVDEDirectories(EmbeddedLDAP.java:1035)
        at weblogic.ldap.EmbeddedLDAP.start(EmbeddedLDAP.java:212)
        at weblogic.t3.srvr.SubsystemRequest.run(SubsystemRequest.java:64)
        at weblogic.work.ExecuteThread.execute(ExecuteThread.java:209)
        at weblogic.work.ExecuteThread.run(ExecuteThread.java:181)
>

The first thing we tried is restoring a backup of the ldap folder. This backup can be found at: ../domain-name/server/adminserver/data/ldap/backup/ and should be restored at ../domain-name/server/adminserver/data/ldap/ldapfiles.

When this was not working, we kept looking and stumbled upon a site that told us that this error could be caused when the volume that contains these files is running full. WebLogic will corrupt these files. And the solution is to add ‘replica.num=0′ to the ../domain-name/server/adminserver/data/ldap/config/replicas.prop file. Or just remove this file..

Source: http://ghattus.com/2008/10/number-format-exception-while-starting-weblogic-server.html