gzip: stdin: not in gzip format

I'm trying to install the monitoring client on a raspberry pi (ARM CPU) and it fails.  Here is the output:

curl -k -s https://anturis.com/api/1/agent/install/Argus_Monitor/33b029040f823662_nop | sh
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 174 100 174 0 0 455 0 --:--:-- --:--:-- --:--:-- 639

gzip: stdin: not in gzip format
tar: Child returned status 1
tar: Error is not recoverable: exiting now
sh: 16: cd: can't cd to anturis-agent-2.1-armv6l
chmod: cannot access `install-anturis-agent.sh': No such file or directory
sh: 18: ./install-anturis-agent.sh: not found