我正试图运行以下Python代码，通过Selenium创建一个Firefox Webdriver窗口：
from selenium import webdriver
driver = webdriver.Firefox()
driver.get("http://www.google.com")
虽然这段代码几周前运行良好，但现在会产生以下不祥的消息：
Traceback (most recent call last):
File "test.py", line 2, in <module>
driver = webdriver.Firefox()
File "c:\python27\lib\site-packages\selenium\webdriver\firefox\webdriver.py", line 60, in __init__
self.binary, timeout),
File "c:\python27\lib\site-packages\selenium\webdriver\firefox\extension_connection.py", line 47, in __init__
self.binary.launch_browser(self.profile)
File "c:\python27\lib\site-packages\selenium\webdriver\firefox\firefox_binary.py", line 61, in launch_browser
self._wait_until_connectable()
File "c:\python27\lib\site-packages\selenium\webdriver\firefox\firefox_binary.py", line 105, in _wait_until_connectable
self.profile.path, self._get_firefox_output()))
selenium.common.exceptions.WebDriverException: Message: 'Can\'t load the profile. Profile Dir: c:\\users\\douglas\\appdata\\local\\temp\\tmpuf4ipq Firefox output: *** LOG addons.xpi: startup\r\n*** WARN addons.xpi: Ignoring missing add-on in C:\\Program Files\\CheckPoint\\ZAForceField\\WOW64\\TrustChecker\r\n*** WARN addons.xpi: Ignoring missing add-on in C:\\ProgramData\\Norton\\{78CA3BF0-9C3B-40e1-B46D-38C877EF059A}\\NSM_2.9.5.20\\coFFFw\r\n*** LOG addons.xpi: Skipping unavailable install location app-system-local\r\n*** LOG addons.xpi: Skipping unavailable install location app-system-share\r\n*** LOG addons.xpi: checkForChanges\r\n*** LOG addons.xpi: No changes found\r\n*** Blocklist::_loadBlocklistFromFile: blocklist is disabled\r\n************************************************************\r\n* Call to xpconnect wrapped JSObject produced this error: *\r\n[Exception... "\'[JavaScript Error: "this._defaultEngine is null" {file: "resource://gre/components/nsSearchService.js" line: 3527}]\' when calling method: [nsIBrowserSearchService::currentEngine]" nsresult: "0x80570021 (NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS)" location: "JS frame :: chrome://browser/content/search/search.xml :: get_currentEngine :: line 130" data: yes]\r\n************************************************************\r\n************************************************************\r\n* Call to xpconnect wrapped JSObject produced this error: *\r\n[Exception... "\'[JavaScript Error: "this._defaultEngine is null" {file: "resource://gre/components/nsSearchService.js" line: 3527}]\' when calling method: [nsIBrowserSearchService::currentEngine]" nsresult: "0x80570021 (NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS)" location: "JS frame :: chrome://browser/content/search/search.xml :: get_currentEngine :: line 130" data: yes]\r\n************************************************************\r\n************************************************************\r\n* Call to xpconnect wrapped JSObject produced this error: *\r\n[Exception... "\'[JavaScript Error: "this._defaultEngine is null" {file: "resource://gre/components/nsSearchService.js" line: 3527}]\' when calling method: [nsIBrowserSearchService::currentEngine]" nsresult: "0x80570021 (NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS)" location: "JS frame :: resource://app/components/nsBrowserGlue.js :: <TOP_LEVEL> :: line 354" data: yes]\r\n************************************************************\r\n************************************************************\r\n* Call to xpconnect wrapped JSObject produced this error: *\r\n[Exception... "\'[JavaScript Error: "this._defaultEngine is null" {file: "resource://gre/components/nsSearchService.js" line: 3527}]\' when calling method: [nsIBrowserSearchService::currentEngine]" nsresult: "0x80570021 (NS_ERROR_XPC_JAVASCRIPT_ERROR_WITH_DETAILS)" location: "JS frame :: resource://app/components/nsBrowserGlue.js :: <TOP_LEVEL> :: line 354" data: yes]\r\n************************************************************\r\n'
有人知道这是什么意思吗？或者我该怎么做才能解决错误并使代码按预期运行？我通过谷歌搜索找到了相关的错误消息，但没有任何东西可以让我解决这个问题。值得一提的是，我可以通过将上述第二行更改为
driver = webdriver.Chrome()而无问题地打开Chrome Webdriver。我正在使用Python 2.7、Selenium 2.35.0（我刚刚运行了“pip install selenium --upgrade”）和Windows 8机器上的Firefox 26.0。任何其他人可以提供的提示或建议都将不胜感激。