Small tweaks to EROC importer #4417

This contains one functional change and one output change:

**Functional change**

* The row index shows is now +2 instead of +2
* The reason for this is because all text editors and Excel start their row numbers with 1
* Since the first row is the header row then the first data row is row 2
* The `row_index` variable in the code is zero-based, and so to get it to match Excel and any text editor's line numbering scheme it should be +2 (skipping the header row), not +1

**Output change**

* Improved the output to be more helpful when an import fails
* When an importer runs into errors it outputs the in-memory record to make it easier to figure out what exactly isn't matching up and why, whereas before it would just tell you that there was an error

**Test changes**

* Make the tested output match the new +2 code change