keepuptodate problem

I have this script winscp.exe /console /script=c:\batch\rne_up.txt /log=c:\batch\winscplog.txt

option batch on
option confirm off
open xxxxx@www.xxxxxx.cz
option transfer binary :roll:
keepuptodate d:\RNE /
close
exit

On command keeptoupdate i see in console "watching for changes" and that is all

Watching for changes, press Ctrl-C to abort.
Scanning 'd:\RNE' for subdirectories...
Watching for changes in 1478 directories...

If I run synchronize from GUI, all worked ok (changes are detected after 30 seconds)

WinSCP 4.3.4 on Windows Server 2008 x64
Thank for help

Please post a log file both from GUI and script.