Windows 7 Misreported read only on network shares

[benjf]

Hello, I'm troubleshooting a misreported read only error when operating on network shares. Here are the details:

1. Windows Server 2003, fully up to date
2. Windows 7 64 bit client, fully up to date
3. File reports in use and can be opened read only. Almost immediately the file reports as available for use for read/write and allows the file to be opened in that mode.
4. Clients are using a VPN to connect.
5. All files on the network share report this status
6. The files are not all open by other users, services, etc
7. Error is unaffected by user account (the same user account succeeds on XP clients, and fails on Win 7 64 bit clients).

Here is what I have tried and what works/doesn't work.

1. Windows XP clients never receive this problem.
2. Windows 7 32 bit clients fail until brought up to date.
3. Two different VPNs have been used: Hamachi and Microsoft's RRAS. It has no impact on success or failure.

Please let me know what info you need. Thanks in advance for your input and suggestions.