Enterprise Library assemblies shouldn't usually appear in C:\Windows\Microsoft.NET\Framework\v4.0.30319\ -- that is the location of the .NET Framework.
The configuration tool should be in the same directory as the Enterprise Library assemblies. The default location for the install is C:\Program Files (x86)\Microsoft Enterprise Library 5.0\Bin (on a 64 bit system). That is where all
the Enterprise Library assemblies along with the configuration tool are located. You should be able to launch the configuration tool from that location.
If you receive an error while opening a configuration file it usually means that the configuration file is not valid or that the assemblies referenced in the configuration file do not match the version used by the configuration tool. E.g. the
config file contains references to Enterprise Library 5.0.414.0 but the configuration tool is compiled against version 5.0.505.0.
Enterprise Library support engineer