Harmony launcher doesn't support -javaagent startup option. That option is a part of J2SE5 spec , so it probably should be supported.
The java.lang.instrument package (the option is part of) exists in Harmony classlib, and the question of having the option support has quite a story in discussion   , but the option is not yet supported. There's even a JIRA issue  for this problem for IBM VME.
This issue affects Geronimo, as it uses that option and provides it's own jpa.jar.