tile floor creaks!!!

More fun with my old home....
The other day I decided the carpet in the bathroom had to go. After tearing it up and cleaning the floor, I put down another layer of subflooring with about a million screws.....there were no creaks anywhere! I then proceeded to tile the floor with some rather spiffy looking tiles! This morning, (almost 24 hours later) I take a stroll on the new floor and I hear creaks!!!! Is there anything I can do??
Also, since I've been blessed with creative ''male'' gene, I can pretty much relieve myself anywhere....however, how long should I wait before I re-install the toilet? Should I grout first?
Thanks in advance for any help
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.