The amx-core.jar file is missing from the nucleus distribution (nucleus.zip).
The source for this module is in main/nucleus/common/amx-core, and this module is needed to boot the AMX mbean infrastructure within nucleus.
For the appserver build, the amx-core module is included in the "glassfish-common-full" package. I don't know why it is there.
Please move amx-core to a nucleus package.