This sounds very much like a script - try installing a fresh new mIRC 6.16 to a directory with no scripts and see if the same thing happens. If it doesn't then it's a script in your main mIRC directory.
Try typing /!remote off and see if it still happens. You may also wish to go into your Remotes by pressing ALT+R and search for something like 'on *:input' - in most circumstances you need to add | halt } to the end of an on input event to halt the original text - this could be what you're experiencing.
Hope this helps!
Regards,
