For best performance, a Windows 2003/2008/2012 server running the Advantage Database Server with the Corporate Edition of CAPITAL Office should be configured so that foreground applications have NO performance boost. If foreground applications are given a performance boost, it is possible for the Advantage Database Server to "starve" and provide poor performance.
With Windows 2003/2008/2012 server, turn off foreground application performance boost by double-clicking the "System" icon in the control panel folder. Then click on the "Advanced" tab and click the "Performance Options" button.
If your data files are located on a drive using NTFS, that PC's "system" group must have full access to the share which contains the data in order for the Advantage Database Server service to have access to that data.
Note: It must be that PC's system group that has full access, not the domain's system group.