This issue is usually caused by user permissions to a certain file within the Financials structure. To resolve the issue you will likely need assistance from a member of your IT team.
Browse to the Financials location. (A good way to do this is to right-click the shortcut of the application and select Open file Location)
Search for 'mglock' in the folder.
To view or edit the permissions for the mglock.dat file:
Right-click on the file and select Properties.
On the Security tab, check that the user has the Write permission ticked.