Can you over beat RI?
I made some this morning for a batch of cookies and its was really fluffy even after I thinned it down to ice the cookies.
I was'nt paying attention and I left it on high while mixing in some more water,so maybe I over beat it?.
And now after sitting for over 5 hours it's still sticky?
When I touched a cookie the icing stuck to my finger and had the consistency of meringue.
Will it dry hard?

Check with Antonia or do a search on Antonia74 icing threads. This fluffy thing was discussed. I know my teacher had said to beat it until it doesn't shine anymore... ??

The water will eventually evaporate, it may just take longer.

ok, thanx!
I let them sit overnight, the icing is still soft but no longer sticky. I 'm keeping my fingers crossed the dry hard enough to package tomorrow b/c I don't have time to rebake and decorate 10 dz cookies!

Try putting them in the oven with only the light on. It will generate enough heat to help them dry faster.