Fix grammar.

h2/src/main/org/h2/constant/ErrorCode.java

@@ -991,7 +991,7 @@ public class ErrorCode {
 
     /**
      * The error with code <code>90061</code> is thrown when
-     * trying to start a server if a server is already running on the same port.
+     * trying to start a server if a server is already running at the same port.
      * It could also be a firewall problem. To find out if another server is
      * already running, run the following command on Windows:
      * <pre>
@@ -1060,7 +1060,7 @@ public class ErrorCode {
     /**
      * The error with code <code>90067</code> is thrown when the client could
      * not connect to the database, or if the connection was lost. Possible
-     * reasons are: the database server is not running on the given port, the
+     * reasons are: the database server is not running at the given port, the
      * connection was closed due to a shutdown, or the server was stopped. Other
      * possible causes are: the server is not an H2 server, or the network
      * connection is broken.

h2/src/main/org/h2/tools/Server.java

@@ -276,7 +276,7 @@ public class Server extends Tool implements Runnable, ShutdownHandler {
             buff.append("Not started");
         } else if (isRunning(false)) {
             buff.append(service.getType()).
-                append(" server running on ").
+                append(" server running at ").
                 append(service.getURL()).
                 append(" (");
             if (service.getAllowOthers()) {
@@ -288,7 +288,7 @@ public class Server extends Tool implements Runnable, ShutdownHandler {
         } else {
             buff.append("The ").
                 append(service.getType()).
-                append(" server could not be started. Possible cause: another server is already running on ").
+                append(" server could not be started. Possible cause: another server is already running at ").
                 append(service.getURL());
         }
         return buff.toString();

h2/src/test/org/h2/test/unit/TestPgServer.java

@@ -40,7 +40,7 @@ public class TestPgServer extends TestBase {
         assertEquals(5535, server.getPort());
         assertEquals("Not started", server.getStatus());
         server.start();
-        assertStartsWith(server.getStatus(), "PG server running on pg://");
+        assertStartsWith(server.getStatus(), "PG server running at pg://");
         try {
             Class.forName("org.postgresql.Driver");
             testPgClient();