I think I've seen it before.
I take it you're not talking about the standard "Page cannot be displayed" Internet error that indicates a lack of connectivity...
but rather the DBL error that usually accompanies a SQL server database...
That could be caused by a number of things, it may be that the server is running a backup, or that the server is performing some prioritary function that will not allow access or modifications to files, or that Jeff tripped over an ethernet cable.
If you get it again, and have the time, try a print screen and cut and paste the error, that would be very helpful in determining the exact cause.
