The curse is that Vue girls will only bring financial ruins to their husbands if not other undesirable aspects of life. Keep in mind that this only applies to a subgroup of the Vue clan. However, because nobody can or will dare identify which subgroup, some people prefer to just steer clear of all Vue.
A summary of the curse as I vaguely remember goes that a Vue girl married a very successful man. When her brother came to visit, her husband made very rude remarks about his lack of wealth and financial stability. When it came time for the brother to return home, she packed fecal matter and pepper for his lunch.
When news spread in his own village and among family members, they all devised a plan to settle the matter. After a year, the village helped the brother become prosperous. They invited the sister and her husband to a feast. At the feast, the "phauj laug" (who is always the designated person that can place a curse according to Hmong traditions) came to cuss out the sister and place a curse on all Vue women.
Thus, it is highly advised that all Vue girls never refuse assistance to their brothers in all financial matters, otherwise they will bring ruin to their own family.
If you are married to a Vue girl then you are forever indebted to her family, particularly her brothers. A lot of men are unwilling to pay this debt, especially if the brothers are thugs and losers. Basically, you might as well be wearing the skirt because her family will use this to own you. Unless you have good in-laws.