"You are not authorized to access table ‘Bills of materials’ (BOMTable). Contact your system administrator" error in AX 2012 R3

That happens because if related Configuration Key  is disabled .

The solution is to enable configuration keys from :
Administration > Setup > System > License Configuration

Check for 'Bill of Material' under 'Trade' in License Configuration form.

Then it will synchronize related tables.

Once this is done Try again to open the form / table

Please verify