It depends, some people report a 90" length limit with CS3 and the Epson driver others seem to get by fine. This is in Windows.
The solution for many is to use Qimage which will go to 144". I also may go longer.
You can also use Imageprint which seems to have no limits other than the roll.
The longest print I have made with Epson and CS3 is 80".
Paul C