Creating a solid pipe problem

[PEG]

I am in the middle of creating a solid pipe in Autocad R14, The problem is when I go to do union command on the extruded circles an error message comes up saying: ACIS error 50007 - three curve ends in divide-and-conquer. Could anyone explain what this means or just how to get around it!!!!!!

 

[loeb]

You're trying to do something that is more complex than the ACAD ACIS engine can't do. You need to use simpler geometry.