Group instances of the same type do not contain identical members... ERROR

[Anonymous]

Hello Everyone,

I have a weird problem in my model. 

This is a subtracted pice of my model:

Parts of two houses with the same floor plan solution. This is only one single group that has been copied.

This is said floor plan:

Now there is a new problem that has occured out of nowhere... When I try to do some stuff in the modell for example adding walls, adding areas etc. this dialog shows up:

What does this mean and why has it syddenly started to show up? I do not want to break my groups which I am suggested when i click fix groups.

Any help is appreciated. File is attached.

Thank you!

[Anonymous · Accepted solution]

Ok, this got solved... sort of. The different groups were slightly of axis.. an angle of 0.001 degrees. This messed everything up. I deleted all groups except one and made sure everything was straight and then placed them again. Now it works!

[revitnation]

Great tip! Thanks a million!