Hi, unfortunately i got some problems with combining my objects and unification. After the unification my object is not really one object. When i used the smooth brush i saw that they aren't combined. The "Boolean-Tool" says then that there is an error and i needed to close meshmolder.
Is it possible that i've done something wrong? Has somebody else this error?

Great, but i need fix bug in show better message.
Problem is solved, to combine objects you need 2 selected objects and choose "boolean" -> "addition". My problem was that I had only one object left because I combined them without the booltool. I think that's not really an error that must be fixed.