After adding the folder to /media/usb, did you restart the box. To change the path, for example, from hdd/IPTVCache to /media/usb/IPTVCache, you have to press the OK button on hdd/IPTVCache and then search for the path /media/usb/IPTVCache and finally click on the green 'Apply' button, not just rename the folder. The /hdd folder will always be returned because you did not confirm the correct path. In order for e2iplayer to work properly, you must install dependencies after the first launch if it asks for it. Also, if you haven't, you have to install the ServiceApp plugin in the feeds to set exteplayer3 as the default player. I've already installed a lot of players from various repos, so I already know by heart what and how to install them. The iptvplayer_rootfs folder will be empty or there install some dependencies that e2iplayer asks for after every launch. With openpli and some other images, dependencies are mostly installed in usr/bin. In /media/usb you must have the following folders IPTVCache, Cache, Buffer (optional), picon, movie.
For installation ServiceApp go to Plugins>Download plugins>Systemplugins>Serviceapp or in telnet
opkg update;opkg install ffmpeg
opkg install exteplayer3
opkg install gstplayer
opkg install enigma2-plugin-systemplugins-serviceapp
Opkg update
init 4 && sleep 1 && echo "config.plugins.iptvplayer.exteplayer3path=/usr/bin/exteplayer3" >> /etc/enigma2/settings && init 3
