cannot rename or delete created folder in email mange folder

cannot rename or delete created folder in email mange folder

I have created an additonal folder via mail options/manage folders for email messages.Once created I cannot delete it, or rename it.

When i click on the folder to attempt change i notice a message "error on page" in the bottom left hand corner of my browser.
error message states

Line: 1
Char:1
error = object expected.
Code:0
URL http//wwwwoznet.com.,au:8080/vo/manageFolder.do?
mainId=603&mode=initial%accountId=603&userId=1

thanks for any assistance