There is a known issue in SP2 that results in two different error messages, both of which reference the file you are trying to open or save being used by another process.
Issue: When you attempt to save a project, you get the following error:
Error in Object: SaveSI5Project
Error Description: The process cannot access the file 'C:\Documents and Settings\username\My Documents\D-Tools SI 5 Projects\Client Name\Project Name.dtl' because it is being used by another process.
Error Number:-2147024864
Issue 2: When you attempt to open a project file, you get the following crash errror:
The process cannot access the file 'C:\Documents and Settings\username\My Documents\D-Tools SI 5 Projects\Client Name\Project Name.dtl' because it is being used by another process.Error: IOException (DTools.SystemIntegrator.Navigator.NavigatorShell.promoteRevision) (DTools.SystemIntegrator.Navigator.NavigatorShell.OnPromoteProjectRevision) (DTools.SystemIntegrator.Navigator.CommandManagement.Command.Execute).....
Cause: We added code that analyzes the project file looking for any illegal characters that might have been added to one of our fields (usually copied/pasted from websites into our description fields) after it has been saved that locks the file while it is processing.
Fix/Work Around: a permanent fix now available as a hotfix. Please use this link http://www.d-tools.com/support/submit-an-issue.html to request the hotfix from our support department. If needed, before applying the hotfix, the work around for this issue is to wait around 3 minutes in-between saves and that should give the process time to complete. On very large projects, more than 3 minutes may be required.