I do have a transaction taking place on the newly opened drawing, but that does not seem to matter.
I have narrowed it down even further now. The issues seems to only be related to dimension objects, but not all dimension objects. I created a test drawing and added a dimension to it, and it works fine, but the drawing my customer supplied has dimensions that do not work. For some reason I am getting an error of 'eWasOpenForWrite' each time I use the command. I selected over 30,000 objects, and only ~1000 objects do not want to be copied, and they are all some form of dimension, AcDb*Dimension. I make sure not to explode any dimension's BlockTableRecord. I am at a lose as to why this is happening. At least I got it down to one type of object, where I can repeat the error. Now to figure why this is happen with dimensions. I did try and Downgrade dimension objects, but that had no effect.