Hey i have a problem with my regression analysis

I have 4 Treatment Groups, thus I've tried to build Dummy Variables for those. Then I wanted to put those dummies in the Regression as dependent Variables. I used the Trigger of my Survey to build those new Variables by recoding them ...

The problem is that I only get NA's as coefficients, which is super frustrating cause I don't find the problem

# Dummy- Variablen für die Treatment - Gruppen erstellen, um eine Regression zu erstellen

# Treatement 1

Rohdaten_xlsx$DT1 <- recode(Rohdaten_xlsx$c_0001,"1=1;2:4=0")

Rohdaten_xlsx$DT1

#Treatment 2

Rohdaten_xlsx$DT2 <- recode(Rohdaten_xlsx$c_0001,"2=1;1=0; 3:4=0")

Rohdaten_xlsx$DT2

#Treatement 3

Rohdaten_xlsx$DT3 <- recode(Rohdaten_xlsx$c_0001,"3=1;1:2=0;4=0")

Rohdaten_xlsx$DT3

#Treatement 4

Rohdaten_xlsx$DT4 <- recode(Rohdaten_xlsx$c_0001,"4=1;1:3=0")

Rohdaten_xlsx$DT4

#Regression mit Dummies --> Problem nur NA Werte

Model_Preise_2<- lm(Rohdaten_xlsx$KB_T1~ Rohdaten_xlsx$DHP1n+ Rohdaten_xlsx$DHG1n +Rohdaten_xlsx$DT1+ Rohdaten_xlsx$DT2+Rohdaten_xlsx$DT3)

summary(Model_Preise)

My professor said I Also can use as.factor in my regression, because this would build the dummies

-> I just don't know how to use these

Thanks for your help