I am also experiencing the same problem on 5.0.1GA Open Source.
I followed the first suggestion and ran
rm -rf /opt/zimbra/jetty/work/*
and cleared my browser cache.
I did not have the error troubles experienced after that, but still received the same error as before.
Here are the details of the error as reported:
JavaScript error encountered in method ZaController.prototype._setView message: xFormObject.items[2].items[5].items[4] has no properties fileName:
https://myserver:7071/service/zimlet..._zimbra_hsm.js lineNumber: 456 stack: ([object Object])@https://myserver:7071/service/zimlet/com_zimbra_hsm/com_zimbra_hsm.
js:456 call([objec...
As far as I can tell, I do not have the ability to enable or diable the com_zimbra_hsm zimlet, so I'm assuming it's something that should always be on
Thank you for any help.