In other words: For the product entity with ID 9478 and the attribute with ID 180, an attempt was made to enter a value for the store with ID 1 that already exists.
However, this is not a Magento bug, but simply the result of an error in the input file. The file contained the same attribute option twice for the affected product. In other words, we are trying to import a T-shirt (ID 9478) with a Color attribute (ID 180) whose value is red (ID 114) and red (ID 114), meaning that the same option value was specified in two rows of the import file. So it is hardly surprising that after correcting the import file, no further problems occurred.
Seen in Magento CE 1.9.1.0.
