Help with this rtmpdump error please

[pow]

Hey guys!
I am trying to download these videos for my exams from a site, but I keep getting:

RTMPDump v2.4 GIT-2015-12-14 (Compiled by KSV)
(c) 2010 Andrej Stepanchuk, Howard Chu, The Flvstreamer Team; license: GPL
Connecting ...
INFO: Connected...
ERROR: Closing connection: NetStream.Play.StreamNotFound

Here is the command I tried:

rtmpdump -v -r "rtmps://53c7c8e287199.streamlock.net/vods3/mp4:amazons3/coursekart/videos/1521/topics/ER Diagrams - Part 1 of 1_qtp.mp4"
 -o "DBMS1.flv"

Here is the page source code:
http://pastebin.com/raw/iJpRfJh6


Can someone please tell me what I am doing wrong ? and how I can download the videos?

[-D3n1s-]

I knew they would help, such a good guys.

btw. You can watch it like that (VLC, PotPlayer):

rtmp://53c7c8e287199.streamlock.net/vods3/mp4:amazons3/coursekart/videos/1521/topics/ER%20Diagrams%20-%20Part%201%20of%201_qtp.mp4