The error "Unable to test bulk load: Internal error: java.lang.Exception: Hadoop executable file does not exist." occurs when the Virtual DataPort server is unable to find the Hadoop libraries in your system. This is necessary because, during the bulk load process Databricks will use the Hadoop libraries to generate files.
To overcome this error, I would ensure that step #6 in the [Databricks](https://www.google.com/url?q=https://community.denodo.com/docs/html/browse/7.0/vdp/administration/bulk_data_load/databricks%23databricks&sa=D&source=editors&ust=1614780230642000&usg=AOvVaw0YiW2jJoX1bF0AICZN1xh3) section of Virtual DataPort Administration Guide is performed.
Hope this helps!