The toilet may be leaking and the water collecting on the floor - the tiles may be wet but they're not leaking...
If you have a close coupled cistern where the water box sits immediately on top of the WC pan the leak may be coming from the low pressure seal between the two - a large, round, soft rubber washer called a donut (because it looks like a ring doughnut) makes the seal. It is squashed to make the seal by a flat metal plate which is drawn down onto the washer by a pair of bolts each with a wing nut - try tightening the wing nuts it often fixes a leaking donut washer.
The bolts are at the back - pointing downwards - one each side.
Good luck...
Peccavi
October 2009