regression coefplot on Stata PLS HELP

I want to make a regression coefplot for 3 variables, the independent variable being a standardised AIDS figure (number of known people who have died from AIDS) and then I want to see the relationship between this and gender (labelled as 'gender') and how often an individual has gone without medical care which comes under the name 'q8c' and has categorical answers such as 'many times', 'don't know' etc. I tried to make a regression table using the command 'reg z_aids gender ibn.q8c' but stata said that the factor variables may not contain negative values. I don't know what this means and I'm pretty certain even attempting to put these variables into a regression coefplot won't work so does anyone have any advice on what to do next or what to display the data as instead? Thanks!