Try to start test using Grid
1. start hub with: java -jar selenium-server-standalone-2.19.0.jar -role hub

2. start node on same machine with: java -jar selenium-serr-standalone-2.19.0.jar -role
node  -hub http://localhost:4444/grid/register

3. in app test launch driver for test:
driver = new RemoteWebDriver(new URL("http://localhost:4444/wd/hub"), DesiredCapabilities.firefox());

What is the expected output?
Launch firefox browser and navigating to the given url

What do you see instead?
Got this error:
Exception in thread "Thread-1" org.openqa.selenium.remote.UnreachableBrowserException:
Could not start a new session. Possible causes are invalid address of the remote server
or browser start-up failure.
Build info: version: '2.19.0', revision: '15849', time: '2012-02-08 16:12:19'
System info: os.name: 'Linux', os.arch: 'i386', os.version: '2.6.38-13-generic', java.version:
'1.6.0_30'
Driver info: driver.version: RemoteWebDriver
    at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:436)
    at org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:139)
    at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:94)
    at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:102)
    ......................
Caused by: org.apache.http.ConnectionClosedException: Premature end of Content-Length
delimited message body (expected: 5359; received: 2543
    at org.apache.http.impl.io.ContentLengthInputStream.read(ContentLengthInputStream.java:178)
    at org.apache.http.impl.io.ContentLengthInputStream.read(ContentLengthInputStream.java:197)
    at org.apache.http.impl.io.ContentLengthInputStream.close(ContentLengthInputStream.java:105)
    at org.apache.http.conn.BasicManagedEntity.streamClosed(BasicManagedEntity.java:152)
    at org.apache.http.conn.EofSensorInputStream.checkClose(EofSensorInputStream.java:237)
    at org.apache.http.conn.EofSensorInputStream.close(EofSensorInputStream.java:186)
    at org.apache.http.util.EntityUtils.consume(EntityUtils.java:67)
    at org.openqa.selenium.remote.HttpCommandExecutor$EntityWithEncoding.<init>(HttpCommandExecutor.java:498)
    at org.openqa.selenium.remote.HttpCommandExecutor.execute(HttpCommandExecutor.java:386)
    at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:416)
    ... 8 more

Selenium version: selenium-server-standalone-2.19.0.jar, selenium-2.19.0.jar
OS: Linux Mint LXDE
Browser: Firefox
Browser version: 10
Java version: 
java version "1.6.0_30"
Java(TM) SE Runtime Environment (build 1.6.0_30-b12)
Java HotSpot(TM) Server VM (build 20.5-b03, mixed mode)

Note:
-same code work ok using WebDriver or RemoteWebDriver without grid (connect directly
to selenium server)
-hub and node start without error
-hub console work