Reporting services catalog database file existence failed

Sometimes while installing SQL server 2008, you might face some validation errors like Reporting services catalog database file existence failed.

The solution is really simple. follow below solution:

Open the folder
"C:\Program Files\Microsoft SQL Server\MSSQL10.MSSQLSERVER\MSSQL\DATA"

Delete the below 4 files from the folder

ReportServer.mdf
ReportServer_log.LDF
ReportServerTempDB.mdf
ReportServerTempDB_log.LDF

After deleting the above files ,click Re-run in the setup window. It should work now. You should
not get any validation error.