There could be a number of reasons for Runescaper not joining your channel,First Check These Things.
1.Is Runescaper on your network? You can check this by typing /whois Runescaper
2.Does your channel have a key set?You can check this by either typing /hop or If your using mIRC click Channel Modes.
3.Is your channel blacklisted?Runescaper automaticaly blacklists channels that have kicked it 10 times,if this is the
answer you will need to speak to a Runescaper owner([M]ike or Goatluver500).
If all is well then use /Invite Runescaper #Your Channel or /Invite Runescaper|G #Your Channel.