Access Denied when updating documents

[w2rus]

Hi

I have just added the first install of Office 2007 to my network and have the following problem

My users create a document and save on a shared location on a Windows 2003 Server

1 user who works part time created some documents on Friday and another user attempted to update the files yesterday.

The user is logged on to the same computer as the user who created the document but gets the Access Denied message when trying to save the updated file - same name, location etc

If the user logs onto a machine without office 2007 installed, she can open the document, update it and then save no trouble

I have checked the access rights and everything looks ok, and all users can still update the document on other machines / other versions of Office

Windows XP Pro SP2 is the OS

Thanks in advance for any help

Regards

W2rus