I'm having the exact same problem. But, even though I have (I believe) successfully edited the conf file and I get no error after the opkg update, or after the luci install, I'm not getting luci starting up in my browser.
Luci only gives me one line on the install. Trying to remember if that's normal or not.
> root@OpenWrt:~# opkg install luci
Installing luci (git-20.113.70804-9d02ef1) to root...
Downloading https://downloads.openwrt.org/snapshots/packages/mips_24kc/luci/luci_git-20.113.70804-9d02ef1_all.ipk
Configuring luci.
Hmmm... tried installing another package, it seemed to go well, until I tried to run it...
root@OpenWrt:~# opkg install nano
Package nano (5.3-1) installed in root is up to date.
root@OpenWrt:~# nano
Error loading shared library libncursesw.so.6: No such file or directory (needed by /usr/bin/nano)
Error relocating /usr/bin/nano: wclrtoeol: symbol not found
Error relocating /usr/bin/nano: raw: symbol not found
Error relocating /usr/bin/nano: napms: symbol not found
Error relocating /usr/bin/nano: key_defined: symbol not found
Error relocating /usr/bin/nano: mvwprintw: symbol not found
Error relocating /usr/bin/nano: doupdate: symbol not found
Error relocating /usr/bin/nano: nodelay: symbol not found
Error relocating /usr/bin/nano: waddch: symbol not found
Error relocating /usr/bin/nano: wscrl: symbol not found
and more...
So, obviously not installing well. What silly newbie mistake did I make here? Need a permission change or something?