I am getting this error during running\opening of Nav R2.

"C:\Program Files\Microsoft Dynamics NAV\60\Classic\finsql.exe

The application has failed to start because the application configuration is incorrect"

Which OS are you using and which version of nav?

Did you try by reinstalling nav?

xp service park 3

microosoft dynamics NAV 2009 R2

I have done that several times and also tried using different installations

Check the event viewer and firewalls…

Try check installation package is it support with OS or not also update .Net Framework with latest update,

for using Database make sure SQL Server service or SQLEXPRESS installed and running.