Seems like this has happened to me before but I can't remember how to fix it.
I was having guide data issues and only had data for my local channel on one of my PC's. The other two I use for WMC were fine, so I did a complete setup from scratch and although I'm now getting data for all channels, the guide has no channel numbers. I though it was related to My Channel Logos, so I deleted MCL and did another setup which still did not work.
Any ideas?