I am trying to detect a midair collision problem (simultaneous editin) using selenium.

So I start a selenium session A with following (Super Class)

selenium = new MASSelenium(serverHost, serverPort, *iexplore, browserURL);
selenium.start();
selenium.open("index.cgi");

then I try starting a different selenium session B pointing to a different browser from the superclass (Sub Class):

selenium2 = new MASSelenium(getServerHost(), getServerPort(), *firefox, getBrowserURL());
selenium2.start();
selenium2.open("index.cgi");

It works fine on my local machine (behaves as expected) but then when i run this same test on a remote machine (using bamboo build tool), i get this exception:

java.lang.RuntimeException: Could not start Selenium session: Internal Server Error
    at com.thoughtworks.selenium.DefaultSelenium.start(DefaultSelenium.java:89)
    at gov.baba.arc.mas.selenium.tests.SimultaneousEditingConflictDetected.setUp(SimultaneousEditingConflictDetected.java:78)
Caused by: com.thoughtworks.selenium.SeleniumException: Internal Server Error
    at com.thoughtworks.selenium.HttpCommandProcessor.throwAssertionFailureExceptionOrError(HttpCommandProcessor.java:97)
    at com.thoughtworks.selenium.HttpCommandProcessor.getCommandResponseAsString(HttpCommandProcessor.java:168)
    at com.thoughtworks.selenium.HttpCommandProcessor.executeCommandOnServlet(HttpCommandProcessor.java:104)
    at com.thoughtworks.selenium.HttpCommandProcessor.doCommand(HttpCommandProcessor.java:86)

Any idea why this is happening?