On my new-laid mint linux 12 "Lisa" I've installed tshark by simply typing "sudo apt-get install tshark".

In my opinion this should be self-explaining:
kutacz-Desktop tomek # tshark -v
tshark: Lua: Error during loading:
[string "/usr/share/wireshark/init.lua"]:45: dofile has been disabled
TShark 1.6.2

Copyright 1998-2011 Gerald Combs <gerald@wireshark.org> and contributors.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Compiled (64-bit) with GLib 2.29.92, with libpcap 1.1.1, with libz 1.2.3.4, with
POSIX capabilities (Linux), without libpcre, with SMI 0.4.8, with c-ares 1.7.4,
with Lua 5.1, without Python, with GnuTLS 2.10.5, with Gcrypt 1.5.0, with MIT
Kerberos, with GeoIP.

Running on Linux 3.0.0-12-generic, with libpcap version 1.1.1, with libz
1.2.3.4.

Built using gcc 4.6.1.
How to enable dotted files? Or is there other reason?