Cannot add categories

[cmewebs]

When trying to set up a category in VM 2, I keep getting the same error: vmError: VmTableData Sef Alias in record is missing! Can't save the record with no Sef Alias.  I have typed in a Sef Alias but still get this error.  Please let me know what I am doing wrong.

Joomla 2.5 VM 2.6.6

Thanks