Hello,
and yes, i am on the right forum i hope 
so my issue : when mounting an OWNCLOUD server in WEBDAV i was able to EDIT
"libreoffice" documents as usual
since i use version 4.2, i got error message (and unable to access the
document)
same file with MINT 16 OS (shipped with 4.1) works fine.
same file with windows 7 + Office works fine
same file with Mint 17 (libreoffice 4.2) does not work
same file with Mint 16 upgraded to 4.2 does not work
--> so for me it is an 4.2 issue
is there any workaround for this ? or it is a known bug ?
thanks for the help of all 
best regards !