Oops, time to re-install eBook Publisher as the same (1200) .imp got posted twice above from your use of Mobi2IMP.
Did you recently install eBookwise/GEB Librarian or BookDesigner? Those programs "break" current versions of eBook Publisher since they install older versions of PubX.dll/PubUtil22.dll! When this happens, the re-install of eBook Publisher v2.2.5 will "cure" this (for a while!).