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Im using the latest version 1.7.6.5 
Ive changed all instances in the database where UPC exist from 12 to 50 nvarchar
Ive changed "AdminImportController.php" default value
ive changed "Combination.php" upc 50
ive changed "store.php" upc 50
ive changed "validate.php" upc = 50

I tried every post in the forum involving this issue and i cant do it.