I have had this association setup for awhile now. I am using windows XP-SP3 and my path is different. (C:\Documents and Settings\HOME\My Documents\My Dropbox) It might not like the path with extra spaces and a dash, Windows is weird sometimes. If the below doesn't work try simplifying the path just for fun.
Select epub file
Right click. select "open with" - choose program
Check box "always use selected program to open up this kind of file."
navigate to appropriate directory
select exe file for viewer
This should work everytime. I have LRF setup with the lrfviewer and Epub setup with the ebook-viewer.
Last edited by DoctorOhh; 10-16-2009 at 11:05 PM.