Okay, the bug which was discovered by sputnik has been fixed and support for IMP format has been added.
For the IMP format support, please install the eBook Publisher
from Ebook Technologies. Also note that imp1 = Color VGA (1200) and that imp2 = Grayscale Half-VGA (1150), similiar to their ETI-1 and ETI-2 designations. Also note that the IMP format support works only on Windows.