junior faculty insecurity, early evening edition

I began sitting in on one of my colleagues' seminars last week. I made a few comments here and there, although nothing I thought was boorish or weird or annoying or anything. This week, for scheduling reasons, the seminar is/was meeting at 7pm tonight instead of its usual afternoon time. I have made a special trip up here, but the seminar is not in either of the locations where I thought I was told it might be. It's as though they are hiding from me.