after i install your facebook widget, i can't log on my site

this is what bounced out after install your widget:

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

** i can't log on anymore, so what should i do now?