Email Already exist

Email Already exist

Hi, i tried to do this in free flow and works fine at first,when i try to submit the email again it shows" One or more fields were dynamically changed.
Please resubmit the form.  

then after i resubmit the form it "Added Data Successfuly"? 
On User Input
 {
 if (count(Register[emailid == input.emailid]) > 0)
 {
 input.emailiderror = “This email id already exists”;
 show emailiderror;
 }
 }