Delete your RoRLauncher.exe and replace it with this one:
http://launcher.returnofreckoning.com/RoRLauncher.exe
Some general things you should make sure are the following:
- make sure your Warhammer folder does not reside in your user profile path, sometimes this leads to permission issues
- locate the cache subfolder of your warhammer online folder and delete any files and folders beneath it but not the cache folder itself
- make sure that all the launcher files are in your Warhammer folder
- right click the Warhammer folder, click properties, remove the write protected flag from the folder and let the setting get inherited to all the subfolders and files
- make sure you stopped all processes that could hold files in the warhammer folder (for example your torrent downloader etc.)
- always start the launcher and the war.exe as an administrator. right click the .exe -> properties -> compatibility -> run as administrator. Configure the war.exe to a compatibility level of "Windows XP Service Pack 3"