I finally found the solution to the Outlook 2007/Office 2007 getting an error when saving to share on 2003 server. I added the user to the Share permissions with full control and this resolved my issue.
I got help from another posting that said this.
Zoppo:
Hi Wyandotte,
it may be this is related to a known problem with Win32 API function 'ReplaceFile' (I'm not sure if Excel/Word use it, but I know that often applications first write data to a temporary file and later use 'ReplaceFile' to create the wanted file).
You can find info about that problem here:
http://support.microsoft.com/kb/274487/en-usA solution would be to either give the user 'Full Access' to the share on the server (not the directory-security, the share-access rights) or to add the user to the local administrator group on the server ...
Hope that helps,
ZOPPO