error - invalid variant type conversion

Hi, we have successfully installed and configured version 2.0 build13.1 but obviously want to test the newer version build 14.2 - on this attempt we get the error "invalid variant type conversion". Can someone please help point us in the right direction.
Thanks in advance ...

There is a null value in

There is a null value in config database. I bet DATABASES.EXTFILEPATH. I fixed some null conversions in release.