Hi Stata Users

I'm trying to run a Spatial Durbin Model where am using the SPMLREG. However when I run the following command:


spmlreg hosp_d Young_d Old_d i.Urban_l tpgrw Litt sexratio Ecoactiv_t Watpro, weights(Wi) wfrom(Stata) eignvar(eigenv) robust model(durbin) sr2


I got the message: factor variables and time-series operators not allowed which is coming when the variable i.Urban_l which is categorical is used. When only continuous variables are used this error message isn't showing up.

Could you please give me a hand on how I can use a categorical variable in the Spatial Durbin Model?

Thank you in advance.

(By the way am using Stata 15 SE)