Got an error while opening database in Simply Accounting System

Hi,
I just installed Sage Simply Accounting system software on my newly issued PC.
I then tried opening the company’s database, but I got this error message (see below).
As a long time user of this software, I knew I had the privilege to open the file. Did I miss a step?
Can someone help me, please?
Thanks in advance.

Simply Accounting
Simply Accounting cannot open the database because some database files are read only.
Please ensure you have sufficient rights to the files, then try again.
