Illustrator :: Possible To Arrange Art Boards In Irregular Way

I'm having problems with a document which has 26 artboards, the document was created by another designer and for some reason everytime I try and rearrange the artboards in this document, it crashes illustrator. The document is not large enough to warrent my machine crashing when I try and do this, and I have plenty of ram. Also the artboards are stacked very irrgeularly they do not work in sequence either horizontaly or vertically down the document canvas area in rows of columns, how is it possible to arrange the art boards in an irregular way like this, I would like to know for future reference? Maybe if I can find this out I can manually rearrange the boards. I should mention when I do try and rearrange the boards, sometimes it doens't crash illustraor straight away and it gives me the message that the artboards will fall completely outside of the document area. This happens no matter what direction I try ( grid by row, grid by coloumn, arrange by row, arrange by column) and also when I try and reduce the amount of space between the boards it doesn't work either.
 
I cannot upload images as the document is for a client.