Hello there..
just to respond to this issue in case this is yet to resolve. I encountered the same problem when trying to sync my journal. But somehow I managed to fix it. Do check your notes.ini and make sure the parameter which points to your journal is correct. It must point to (i) where your journal is located, and (ii)right file name. Edit the parameter to point to its right path. (Make sure you close your LN client before editing your notes.ini).
e.g.
Journal=C:\Program Files\IBM\Lotus\Notes\Data\journal.nsf
Save it. Then, launch your LN, and try to sync again. Hope that helps.