It's because this line:
<SluttyCowgirlerin> [AMSG] WILL S3X0R FOR $$$ 0,1<SluttyCowgirlerin> [AMSG] OR FREE 0,1<Rain> Christina?
has an identifier ($$$) that mIRC tries to evaluate.
Use the n switch while $read'ing:
alias loadquote {
var %i = 1
while (%i <= $lines(Quotes.txt)) {
did -a Quote 1 $strip($read(quotes.txt,
n,%i))
inc %i
}
}