I'm doing a random effects model. I have a dummy per treatment, which would be "Message", "MessageTax", "Tax" and "Donation" which refers to whether or not the experiment included a donation. The data comes from 2 similar experiments, but one was with a donation and the other was not, so the Message, Tax and MessageTax treatments are in both experiments. This appears in Stata when I run this regression:

xtreg q Mensaje MensajeImpuesto Impuesto Donacion Donacion##Mensaje Donacion##MensajeImpuesto Donacion##Impuesto,re

How can I fix it?