This is an indication that the table that stores the path to your database is corrupt. This problem is very rare but you can easily fix it as follows :
– Start Windows Explorer
– Browse to the following folder :
Instant Invoice n Cashbook 10 Users
C:\Users\[YourName]\AppData\Roaming\EzySoft\InstInvCashBk10\Recent
Instant Invoice n Cashbook 2007 Users
C:\Users\[YourName]\AppData\Roaming\EzySoft\InstInvCashBk\Recent
Tip, if your AppData folder is not showing, click the menu option Tools | Folder Options | View page. Ensure that “Show HIdden files, folder and drives” is checked and you should see the “AppData” folder
– In the Recent folder, delete the files Recent.Dat & Recent.IDX.
– Now start Instant Invoice again. These files will be recreated automatically. However Instant Invoice will not have the path to your database. When asked if you want to create a new database, click [No]
– Click the [Open] button. Instant Invoice will prompt you that you do not have any databases. When asked if you want to browse to a database, click [Yes]. Locate your database folder and you will now be open the database