I'm sorry to hear you are having problems. Please contact Tableau Support so they can investigate.

Thanks,

Dan

I know this is an old question but maybe this will help someone else.  I received the same error and it was because I had conflicting conditions assigned for a set I created.  

For example, I wanted to group student majors into an "other" category if there were less than 10 students in any major.  The problem arose because I set that condition but also unknowingly had the option selected to take the "Top 10" majors.  This created conflicting group by conditions.  Once I unchecked the "Top 10" option I no longer received the error.

Just wanted to thank you for this post =), I was having this problem and it never crossed y mind that the set could be causing it, this pointed me in the right direction.