Lotus Notes – Resolving "Illegal Circular USE" errors

A client of mine called me up, saying she had a problem with Lotus Notes. She had recently upgraded from Lotus Notes version 5 to Lotus Notes version 6, and now got a lot of error messages every time she opened just about anything, really. The error message she received said: “Illegal circular USE: DocumentConversions”.
 
As it turns out, the solution is pretty straight forward. The problem is that the design of the users’ mailfile is outdated. All you need to do is update it to the design for Lotus Notes version 6, and off you go.