Networking OSX - server2003 - file permissions problems

I've just upgraded our MAC desktops and a windows file server to OSX and 2003. I can access the shares on the 2003 file server, the local security policies are set

Microsoft network server: Digitally sign communication(always): Disabled
Microsoft network server: Digitally sign communication(if client agrees): Disabled
Domain member: Digitally encrypt or sign secure channel data(always): Disabled

the shared folders enable authentication are set to apple cleartext or windows

From the server I can browse all the folders and files and make changes/modify but from the MAC I can browse but can't make any changes - don't have access/permissions.

Has anyone seen this problem before???? :radioacti

Is it a DC? If so the local group policy will need to edited in AD not gpedit.

I assume that not only the Share permissions are read/write but the Security permissions are read/write as well.

Or are you authenticating from the mac as windows Administrator user?

It's not a DC - just a file server for the Mac clients - we're logging in with windows domain accounts - the permissions are set for the user's logging in to modify on all the files