error loading module 'socket.core'

[Akamaru]

I've installed the bot on my Ubuntu (15.04) system. When I try to start the bot, following error appears:

akamaru@yagyuu:~/bot$ ./launch.sh
Telegram-cli version 1.3.3, Copyright (C) 2013-2015 Vitaly Valtman
Telegram-cli comes with ABSOLUTELY NO WARRANTY; for details type `show_license'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show_license' for details.
Telegram-cli uses libtgl version 2.0.3
Telegram-cli includes software developed by the OpenSSL Project
for use in the OpenSSL Toolkit. (http://www.openssl.org/)
Telegram-cli uses libpython version 3.4.3
I: config dir=[/home/akamaru/.telegram-cli]
 *** lua: error loading module 'socket.core' from file '/usr/lib/x86_64-linux-gnu/lua/5.1/socket/core.so':
        /usr/lib/x86_64-linux-gnu/lua/5.1/socket/core.so: undefined symbol: lua_pcall
akamaru@yagyuu:~/bot$

All dependencies are installed. It's not the first time I installed the bot on a system, but now I'm confused.

[yagop]

./.luarocks/bin/luarocks install luasocket

[Akamaru]

Doesn't work. Have the same error