why keeps iCal generating the 404 error while synchronizing with google agenda?

I'm using iCal to synchronize the agenda on google.

Sometimes it works and sometimes it doesn't.

The error I got is that the |server responded with an error : 404.

What is causing that error and what can I do to solve this issue.

Or is it something out of my control and has it got something to do with a temporarily overload of the Google server?

I would appreciate comments