Well I have a potential solution. There are a couple of causes of this error that I know of.
One is a bug - using oranev from an agent home.
It's not supported - it has to be from a database home. See
"Running oraenv from the Grid Control Agent Oracle Home Fails [ID 1323684.1]"
"The oraenv is not meant to be run from the Grid Control 184.108.40.206 Agent ORACLE_HOME.This was diagnosed in BUG 10227734. The BUG will remove the oraenv from future agent installs....
Set the environment manually or using .sh script."
See the note for full details.
What if you are not using an agent home?
Then the other cause I am aware of is this-
The oraenv script sets ORACLE_BASE. If it is not already set in the environment it calls a binary $ORACLE_HOME/bin/orabase.
orabase returns the ORACLE_BASE by looking in the Oracle Home's Inventory. It looks for the value in the file
This file it seems can sometimes lose the value of the Oracle Base, and if it does then orabase returns the XPointer evaluation failed: no locset error.
<PROPERTY NAME="ORACLE_BASE" VAL="/ora/oracle"/>
If the PROPERTY_LIST bit is missing, then you need to add it back in.
Set VAL= to be your Oracle Base - the example above is specific to MY environment.