EnterPrice 4

Fixed. The problem was in service.cpp:69 — when the IBPP core library was rewritten from the legacy C API (isc_service_attach) to the Firebird OO API (attachServiceManager), the server name was accidentally dropped. The connection string was hardcoded to just "service_mgr" instead of "servername:service_mgr".

This caused the backup to connect to the embedded Firebird engine instead of the running Firebird server. Since the server already has the database file locked, the embedded engine reports "database is in use".

The fix prepends mServerName: to the service manager connection string (matching the pattern from the older core.api.5 implementation), so it correctly routes to the Firebird server that already has the database open.