Files missing after activating offline files.

I have activated the offline files synchronization but when I synchronize
some recently used files (excel files predominantly) are not synchronized but
a .tmp file is generated is the source folder instead. When I close down the
folder and reopen it the original file is gone! Does anyone know why this
happens? All programs and files are closed when I start the synchronization.
I have emptied the CSC folder according to:

http://windowshelp.microsoft.com/com...s/default.mspx
?dg=microsoft.public.windows.vista.general&tid=ebd d584c-1158-48b4-b185-
e6c520fd0f7c&cat=&lang=en&cr=US&sloc=en-us&m=1&p=1

Also, how can I find the files that are gone? I tried to restore an older
version of the CSC folder but I get the message that I do not have the rights
to copy/open that folder even after having reassigned the ownershop of that
folder.