sendToPi: true does not work #13

Hello All

I've installed the RIO Projekt on my RBP3.
I was able to run the strandtest.py and singlestrandtest.py
After that i tried to run the Server with the "npm run server" command. i got the expected output on the Terminal Window (RIO Logo). After switching the "sendToPi" parameter to true, i became following error:

pi@raspberrypi:~/rio $ npm run server

rio@0.0.1 server /home/pi/rio
cd ./rio-server && npm start

rio-server@1.0.0 start /home/pi/rio/rio-server
node index.js

warn: SlackDataStore is deprecated and will be removed in the next major version. See project documentation for a migration guide.
events.js:165
throw er; // Unhandled 'error' event
^

Error: Can't open /dev/mem: Permission denied
Traceback (most recent call last):
File "firmware/rpi/lowlevel-server.py", line 52, in
raise RuntimeError('ws2811_init failed with code {0} ({1})'.format(resp, message))
RuntimeError: ws2811_init failed with code -5 (mmap() failed)

at PythonShell.parseError (/home/pi/rio/rio-server/node_modules/python-shell/index.js:190:17)
at terminateIfNeeded (/home/pi/rio/rio-server/node_modules/python-shell/index.js:98:28)
at ChildProcess.<anonymous> (/home/pi/rio/rio-server/node_modules/python-shell/index.js:88:9)
at ChildProcess.emit (events.js:180:13)
at Process.ChildProcess._handle.onexit (internal/child_process.js:209:12)

Emitted 'error' event at:
at terminateIfNeeded (/home/pi/rio/rio-server/node_modules/python-shell/index.js:111:22)
at ChildProcess. (/home/pi/rio/rio-server/node_modules/python-shell/index.js:88:9)
at ChildProcess.emit (events.js:180:13)
at Process.ChildProcess._handle.onexit (internal/child_process.js:209:12)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! rio-server@1.0.0 start: node index.js
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the rio-server@1.0.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR! /home/pi/.npm/_logs/2018-11-24T18_23_50_219Z-debug.log
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! rio@0.0.1 server: cd ./rio-server && npm start
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the rio@0.0.1 server script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm WARN Local package.json exists, but node_modules missing, did you mean to install?

npm ERR! A complete log of this run can be found in:
npm ERR! /home/pi/.npm/_logs/2018-11-24T18_23_50_289Z-debug.log
pi@raspberrypi:~/rio $

Running npm with sudo does solve the issue, but i get no output on my LED's

Do you have any idear what happens wrong?