Getting browser already open error message in Test Execute

I add all the browsers I use for testing to the TestedApps section. The at the end of every test I run this routine to close the browsers as required.

'closes the tested browser
FUNCTION lib_closeBrowser(browserType)
  DIM testedAppIndex
  testedAppIndex = TestedApps.Find(browserType)
  'find index of the tested browser
  IF NOT (testedAppIndex < 0) THEN
    Log.Message("Closing browser : " & browserType)
    IF Sys.WaitBrowser(browserType,3000).Exists THEN
      TestedApps.Items(testedAppIndex).Close
    END IF
    IF Sys.WaitBrowser(browserType,2000).Exists THEN
      TestedApps.Items(testedAppIndex).Terminate
    END IF
    IF Sys.WaitBrowser(browserType,1000).Exists THEN
      CALL kill_Browser(browserType)
    END IF
  ELSE
    Log.Error("Closing browser : " & browserType & " : ERROR: Application not found")
  END IF
END FUNCTION

'CALL function like this
lib_closeBrowser("iexplore")
lib_closeBrowser("chrome")
lib_closeBrowser("firefox")