We had a user complain that on Windows 7 and Office 2007, when they try to open a Office document on a Novell Netware fileshare, they were getting a “File in use” error.

After much investigation, and speaking to Microsoft, we were told to use the solution documented in:
“You receive a message when you try to open an Excel 2007 document on a Windows Vista-based computer from a remote shared folder, even if no other user is using the document: “File in use”

Which is essentially :
Apply registry changes as follows:
Key:
HKEY_CLASSES_ROOT\CLSID\{993BE281-6695-4BA5-8A2A-7AACBFAAB69E}

Name: EnableShareDenyNone
Type: REG_DWORD
Value: 1
Key:
HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{993BE281-6695-4BA5-8A2A-7AACBFAAB69E}

Name: EnableShareDenyNone
Type: REG_DWORD
Value: 1