I disabled the code I have, copied the code you pasted, and got this:
[17:40:37] * Attempting to rejoin channel #cellka
[17:40:37] * Rejoined channel #cellka
[17:40:42] <Ginnypig>
http://127.0.0.1/blah.exe[17:40:42] <FiberOPtics> works.
Like I said, you either have another on text event that is interfering, or you already have an alias named badhttp.
Disable my alias by putting a ; in front of it, close the mIRC Scripts Editor, and type //echo -a * $isalias(badhttp)
Also look in that remote where you pasted the snippet for other on text events above this one. Or simply put it in a new remote.
Are your remotes even on? /remote on
Greets