I bring mIRC into #my-room, but whatever messages are said are not seen in the screen. I use another instance of mIRC (on another machine), and see all of the messages. It's like it is filtering all of the messages. Any ideas?

That copy of mIRC runs my little bot, and at first I thought it was bad scripting, but then I unloaded all of my scripts - and the error still occured. Any ideas?

I would check a couple of things. First take a look at your ignore list. Next check your usermode. Some networks have a usermode (+d) that makes you 'deaf'.

In addition, you might try /debug -p @Debug

See if the server is actually sending your mIRC any messages from that channel at all.