FGCP returns a 202 Accepted to a delete request for a system as it requires to make two subsequent (time taking) calls to the backend: stopping the embedded FW and then destroying the system. The 202 contains a message saying that the FW/system "will be deleted once it has stopped".
Problem is how the message is wrapped:
<error status='202' url='/cimi/systems/UZXC0GRT-3KIYQVLJC'>
<backend driver='fgcp' provider='default'></backend>
<message><![CDATA[Firewall will be deleted once it has stopped]]></message>
<![CDATA[/home/dc/deltacloud/server/lib/deltacloud/drivers/fgcp/fgcp_driver.rb:1145:in `block in delete_firewall'
2xx responses shouldn't be marked as "error" and don't need a backtrace.