Hevacomp V8i

Suddenly get this message after using full CAD Input on this project for a few days.  The Hevacom Project Explorer confirms my project details comprising existing data of 37 rooms but can not open the project.  I can see the data on the network server directory?  If I try to navigate to the data from within Hevacomp via Windows path method it says no room data etc. and no database which conflicts with the confirmed project details using Project Explorer?  The data resides on a network server and I can see the JETDDB.MDB file can anybody help me connect to the database or have I got to start all over?