Hi N9JIG,
I have installed my Radarbox to C:\Airnav and in my program files (x86) there are Airnav files also. Why I dont know, probably something to do with Radarbox being 32bit working on 64bit windows.
As you have installed the Navdata and it is showing 82,448 rows i would suggest you have more than one NavData.db3 file on your computer. The one you should be using is 48,882KB as you state.
I would suggest you use windows search to look for NavData.db3. In my X86 Data folder there only 2 files the NavDat.db3 and a backup. As you installed to the default location, I would suggest the one your computer is using is in program files In the correct Data folder you will have lots of files including ASssets, photos, logos, silhouettes folders, a number around 20 dat files and your Mylog files and a Navdata.db3, Navdata.db3.bak, NavData.db3-journal and a navdata-backup.db3 file.
I would suggest you move the Navdata.db3 file from the x86 data folder to the program files data folder and start up Radarbox and see what count you get.
Alan