Error Message: "object name already exists: _0"

Check your 2D,3D,4D identifiers. They must contain the correct number of column names.

Error Message: Cascading Delete failed (e.g. dataTable, cubeLevelInstance, ...)

An object is still using a table from the original data source. Delete the offending object. In most cases the problem occurs when trying to overwrite existing dimensions, e.g. when uploading a new dimension or levels with already existing names. If the errorMessage contains an ID (e.g. dataTableColumn(123)), you may get further information by looking at the raw objects at <main application path>/v1/dataTableColumns/123.

Error Message: Could not add row on table XXXX_AUTO_DIM: row.size() != columnMetadata.size() , 3 != 2

Most common cause is, taht you have misconfigured a dimension. Make sure the configuration of your =DIM identifiers is correctly set up, and that no entry is assigned two different parent items. Check out Dimension & Hierarchy Management for details.