To resolve the rule order conflicts the normal steps are
Double click on the problem in the problems panel of the watch window (multiple rules will show up)
Try to understand the logical connection between the rules to determine a useful execution order. Sometimes just duplication of rules are the reason, in which case delete the faulty duplication.
On Default rules the order of a product rules is typically lower than the customization.
On Check rules the order of a product rules is typically higher than the customization. On check rules the order of the execution determine the position of the errormessages, which normaly is not that important.
On Event rules the order needs to be based on the function the respective event executes.
In most cases the order number is forgotten when setting up the rule.
Keep in mind the default order number, when no order is specified, is 1000.