Copy File Action results in NullPointerExceptino

[possum3]

For some reason I am getting a NPE when executing a CopyFile Action in the Post Install Sequence
ex;

Installed File: $USER_INSTALL_DIR$/backups/lib/server.properties
Destination Path: $USER_INSTALL_DIR$/lib
Rename to: server.properties

Error:
Copy File: Destination: C:\Program Files\MyApp\lib\server.properties
Status: ERROR
Additional Notes: ERROR - java.lang.NullPointerException

The weird thing is that the file does get copied over ok.

Thanks for any help