I am getting this error when trying to start LO 5.4. I had LO 6.04 installed and giving same error, so uninstalled and installed LO 5.4:
LibreOffice 5.4 - Fatal Error
The Application cannot be started
[context="shared"] caught enexpected
com.sun.star.ucb.InteractiveAugmentedIOException: a folder could not be created