Component returned failure code: 0x80004003 (NS_ERROR_INVALID_POINTER) [nsIDOMLocation.toString] in selenium

While running selenium test case I could see the below error. It is running without error for sometimes, but sometimes it is going to error.

Component returned failure code: 0x80004003 (NS_ERROR_INVALID_POINTER) [nsIDOMLocation.toString]
    at com.thoughtworks.selenium.HttpCommandProcessor.throwAssertionFailureExceptionOrError(HttpCommandProcessor.java:112)
    at com.thoughtworks.selenium.HttpCommandProcessor.doCommand(HttpCommandProcessor.java:106)
    at com.thoughtworks.selenium.DefaultSelenium.waitForPopUp(DefaultSelenium.java:403)
    at com.sf.httptestselenium.tracker.FilterTrackerSeleniumHttpTest.configureColumns(FilterTrackerSeleniumHttpTest.java:137)

Could you please help me..