[TASK] Check for configuration errors in Import

Resolves: #60563
Change-Id: Id4e1310c8ffcea542993f8dd4a931d2871bfcaec
Reviewed-on: http://review.typo3.org/31834
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>