Yeah. I'm having that problem too with Iconoclasm 1.8.1. I suspect that it's doing that when you are moving the icon from a folder to page that is full. (I have a home page that uses a 4 icon layout.)
The workaround for me was to use Iconoclasm Layout Maker and modify my custom 4 icon layout to one that had more icon positions (I did a total of 16 positions...that should be enough). That way, dragging the icon out would at least prevent the Springboard from crashing.
I've Email'd the author. I think he said he's out of country at the moment and won't be able to check on the problem till early March.
Even with the bug, I'm planning to keep Iconoclasm unless some other catastrophic incompatibility or problem is found. There's no other way to bump icons around with a 1 pixel resolution. Besides, it works with FolderEnhancer so I have a 4 icon layout on the home page, and a 4x5 icon layout in the folders (which looks great/uncluttered with Shrink set to scale icons to 95%).