One or more rows contain values violating non-null, unique, or foreign-key constraints

The following error ususally occurs when your typed DataSet is confused about a key constraints.

• "An error has occurred during report processing.
  • Exception has been thrown by the target of an invocation.
    • Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints. "

To fix this problem, try to delete your typed DataSet and create again by dragging a table or SP direct on the Form from your Database.

If it does not solve your problem, open your Typed DataSet in designer by double clicking on .xsd file and delete the key contraints from the column.

Here are some more threads on this topic:

1. http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=364416&SiteID=1
2. http://weblogs.asp.net/rosherove/archive/2004/10/03/DataSet-hell-_2D00_-_2200_Failed-to-enable-constraints.-One-or-more-rows--contain-values_2E002E002E002E002200_.aspx
3. http://www.devnewsgroups.net/group/microsoft.public.dotnet.framework.adonet/topic14842.aspx
4. http://www.dotnet247.com/247reference/msgs/21/108864.aspx