[Error: Upgrade DB to 4.2.alpha1: Price Sets]

When I try and upgrade from 4.1.5 or 4.1.6, I get the following Error:

==========================
Error Field Error Value
Type DB_Error
Code -3
Message DB Error: constraint violation
Mode 16
UserInfo INSERT INTO civicrm_price_field_value (price_field_id , name , label , amount , weight , is_default , is_active ) VALUES ( 120 , '' , NULL , '25' , 1 , 1 , 1 ) [nativecode=1048 ** Column 'label' cannot be null]
DebugInfo INSERT INTO civicrm_price_field_value (price_field_id , name , label , amount , weight , is_default , is_active ) VALUES ( 120 , '' , NULL , '25' , 1 , 1 , 1 ) [nativecode=1048 ** Column 'label' cannot be null]
==========================

I've attached a screenshot to the issue so you can see what I'm talking about. Any help would be greatly appreciated.

Thanks!