samba - Jul 2003 - Could this be a rights issue?

I'm pretty new to Samba, so I appologise if this is a really dumb 
question, but I can't find a way through it.

I have created a samba share on my Linux box for the users home 
directory, and can map a drive to the share from W2K clients and 
see/open all the files, the problems arise when I try and edit or create 
files, from the W2k client.

If I attempt to create a file through windows explorer I get the message
'Unable to create the file. xxx.txt'
'The specified Network name is no longer available'

But the strange part is - the file is created! I can then edit this file 
using notepad and save its contents, but if I try to edit the file in 
other apps (Excel, UltraEdit) I get file errors when I attempt to save 
it, and my linux home directory fills up with hundreds of .tmp files, 
whilst the application tries to save the file.

Any ideas?
I'm running Samba 2.2.7 on Mandrake Linux 8.2

The created file is owned by the correct user and has the rights -rwxr--r--

Here's the relevant section of my smb.conf file.

[global]
         smb passwd file = /etc/samba/smbpasswd
         wins server = 172.16.33.31
         browseable = no
         printing = cups
         dns proxy = no
         encrypt passwords = yes
         socket options = TCP_NODELAY IPTOS_LOWDELAY SO_SNDBUF=8192 
SO_RCVBUF=8192
         printcap name = lpstat
         max log size = 50
         preferred master = no
         security = user
         available = yes
         local master = no
         workgroup = SET
         server string = Linda Samba Server %v
         log level = 1
         netbios name = Linda
         log file = /var/log/samba/log.%m
         load printers = yes
         hosts allow = 127.0.0.1 172.16.33.

[home]
         path = /home
         writable = yes
         comment = Home Directories
         browseable = yes
         valid users = horsley
         available = yes

Hope someone can help out

Martin.