LINGO's license manager was unable to find a valid license file.  The license file is normally located in your main LINGO subdirectory under the name: lndlng<version>.lic, where <version> is the version number of your LINGO installation.   You may want to examine this file for any obvious errors or problems.  The license manager will also return a brief string with more specific information (e.g., "No dongle found"), which will be displayed as part of this message.  This additional information should help you narrow down the problem.  If you are still unable to resolve this problem, please contact LINDO Systems Technical Support for assistance.