Selenium Grid "Could not start Selenium session"

[Rafal]

I am using Selenium Grid 1.0.4. and running a suite of tests distributed among 4 firefox browsers on the same machine in parallel.Everything works fine on a physical machine but when I ran this on exactly the same configuration but on vm the tests run for a while but after some time Selenium cannot establish new session. Thanks for any help on this...

java.lang.RuntimeException: Could not start Selenium session: ERROR: Connection refused: connect\\      at com.thoughtworks.selenium.DefaultSelenium.start(DefaultSelenium.java:89)\\      at com.abc.tests.bs.functional.BSFunctionalTestBase.setUp(Unknown Source)\\      at com.abc.tests.bs.functional.NGTC22001OverviewPanelTestNG.setUp(Unknown Source)\\      at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)\\      at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)\\      at java.lang.Thread.run(Unknown Source)\\ Caused by: com.thoughtworks.selenium.SeleniumException: ERROR: Connection refused: connect\\      at com.thoughtworks.selenium.HttpCommandProcessor.throwAssertionFailureExceptionOrError(HttpCommandProcessor.java:97)\\      at com.thoughtworks.selenium.HttpCommandProcessor.doCommand(HttpCommandProcessor.java:91)\\      at com.thoughtworks.selenium.HttpCommandProcessor.getString(HttpCommandProcessor.java:262)\\      at com.thoughtworks.selenium.HttpCommandProcessor.start(HttpCommandProcessor.java:223)\\      at com.thoughtworks.selenium.DefaultSelenium.start(DefaultSelenium.java:81)\\      ... 18 more\\ ... Removed 13 stack frames