rsync hangs in cron (not SSH-problem)

[Pascal Nobus]

This is the case

- mounted Inetpub's windows-webserver on /mnt/web1 /mnt/web2, etc.
- rsync this to local dir:
	rsync -av --delete /mnt/web1 /mass/kuurne/day
	rsync -av --delete /mnt/web2 /mass/kuurne/day
	etc..

- when logged in, everything works (I do see some errors about 
non-existing files, but rsync won't stop.


When used this command in cron

00 01 * * * rsync -av --delete /mnt/web1 /mass/kuurne/day
00 02 * * * rsync -av --delete /mnt/web2 /mass/kuurne/day
etc..


Rsync hangs, it doesn't finish!

root      2036  5.7 10.4 27616 26704 ?       S    01:00   5:19 rsync -av 
--delete /mnt/web1 /mass/kuurne/day
root      2037  3.4 11.0 29028 28104 ?       S    01:00   3:09 rsync -av 
--delete /mnt/web1 /mass/kuurne/day
root      2048  3.1 11.0 29060 28132 ?       S    01:11   2:36 rsync -av 
--delete /mnt/web1 /mass/kuurne/day
root      2062 10.0  7.9 21304 20168 ?       S    02:00   3:19 rsync -av 
--delete /mnt/web4 /mass/kuurne/day
root      2064  4.9  8.2 22208 21056 ?       S    02:00   1:37 rsync -av 
--delete /mnt/web4 /mass/kuurne/day
root      2094  5.7  8.2 22252 21096 ?       S    02:05   1:34 rsync -av 
--delete /mnt/web4 /mass/kuurne/day


The dir's to be copieed are big (about 5-10 GB), but normally run it 
finishes after 10-20 min.

And...

Some little dir's (less then 1 GB) don't give a problem.
However, got space enough, load = 0.00 and memory isn't full
Mem:   255152K av,  252816K used,    2336K free,       0K shrd,   28832K 
buff
Swap:  530104K av,   10912K used,  519192K free                   38812K 
cached



Ideas??