Direct users to the Toolbox help when cloud TLC fails because of missing

authentication.

[Feature][Toolbox]

org.lamport.tla.toolbox.jclouds/src/org/lamport/tla/toolbox/jcloud/AzureCloudTLCInstanceParameters.java

@@ -140,7 +140,9 @@ public class AzureCloudTLCInstanceParameters extends CloudTLCInstanceParameters
 					"Invalid credentials, please check the environment variables "
 							+ "(AZURE_COMPUTE_CREDENTIALS & AZURE_COMPUTE_IDENTITY "
 							+ "and AZURE_COMPUTE_SUBSCRIPTION) are correctly "
-							+ "set up and picked up by the Toolbox.");
+							+ "set up and picked up by the Toolbox."
+							+ "\n\nPlease visit the Toolbox help and read section 4 "
+							+ "of \"Cloud based distributed TLC\" on how to setup authentication.");
 		}
 		// Verify that the identity file exists.
 		final File file = new File(identity);

org.lamport.tla.toolbox.jclouds/src/org/lamport/tla/toolbox/jcloud/EC2CloudTLCInstanceParameters.java

@@ -75,7 +75,9 @@ public class EC2CloudTLCInstanceParameters extends CloudTLCInstanceParameters {
 		return new Status(Status.ERROR, "org.lamport.tla.toolbox.jcloud",
 				"Invalid credentials, please check the environment variables "
 						+ "(AWS_ACCESS_KEY_ID & AWS_SECRET_ACCESS_KEY) are correctly "
-						+ "set up and picked up by the Toolbox.");
+						+ "set up and picked up by the Toolbox."
+						+ "\n\nPlease visit the Toolbox help and read section 4 "
+						+ "of \"Cloud based distributed TLC\" on how to setup authentication.");
 	}
 
 	/* (non-Javadoc)