We have just modified the 2.2.3 package of DT Register due to a security threat that has come to our attention. Please download the component from your My Orders area again. The only file modified was dtregister.php, so all you have to do is upload that file instead of reinstalling the whole component. If you have a previous version of DT Register, you should upgrade immediately.
We do not know of anyone that has actually experienced any security breach and the issue is not a severe one, however, you should still upgrade the modified version.