I am running a regression with 5 dummy variables and 6 non-dummy variables. One of the dummy variables is omitted by STATA due to collinearity, but there is no reason for there to be collinearity between this dummy and the other variables.
Why is this happening, and is there a way to force the regression through?

I read somewhere that I could attempt to regress the omitted dummy on the other variables to see which one is causing the problem, but that just caused them all to be omitted.