--- a/management/univention-management-console/dev/dh-umc-module-install	
+++ a/management/univention-management-console/dev/dh-umc-module-install	
@@ -173,7 +173,7 @@ call_joinscript %s || true
 umc_frontend_new_hash
 ''')
 
-		with open(os.path.join('debian', package + '.prerm.debhelper'), 'a') as f_prerm:
+		with open(os.path.join('debian', package + '.postrm.debhelper'), 'a') as f_prerm:
 			f_prerm.write('invoke-rc.d univention-management-console-server reload || true\n')
 
 if __name__ == '__main__':