What method are you using for the Agent installation? Push method from the oms side?
If so, have a look at the <oms instance home>/sysman/prov/agentpush/2012-07-30_15-18-09-PM/targets/myhost.oracle.com_targets.xml
Are there should be more details in the logs surounding this error. For example an explination of the exit code 127
EM 12c: Troubleshooting 12c Management Agent Installation issues (Doc ID 1396675.1)
When you look at the verification steps for the agent deployment, can you see at what step of the pre-requisits it fails?