The script is too large to post here,

Start deleting lines (functions) until it stops crashing :)

Should I destroy these font objects or something?

You could try (fontDelete), but it won't make a difference :) Try Tk-804.029_500, and if the problem persists, report it to the maintainer.

Also, your program wouldn't too big to post here if you did not embed gifs -- you can use placeholders

Tk->findINC('demos/images/flagup'),
Tk->findINC('demos/images/flagdown'),
[download]

Also, you should try and eliminate Serialport as the thing that is crashing, you could try Devel::Trace to find that out (or insert print statements to see how it gets)

These lines of code cause the segfault and core dump:

my $button1 = $mw->Photo(-data => &encoded_but1, -format => 'gif');
my $button2 = $mw->Photo(-data => &encoded_but2, -format => 'gif');
my $button3 = $mw->Photo(-data => &encoded_but_exit1, -format => 'gif'
+);
my $button4 = $mw->Photo(-data => &encoded_but_exit2, -format => 'gif'
+);

my $but1 = $c->createImage(40, 400, -image => $button1, -anchor => 'nw
+', -tags => ['but1']);

$c->bind( $but1, '<Enter>', sub {$c->itemconfigure( $but1, -image => $
+button2); });
$c->bind( $but1, '<Leave>', sub {$c->itemconfigure( $but1, -image => $
+button1); });
$c->bind( $but1, '<ButtonPress>', sub{ &tabbed; } );

my $but2 = $c->createImage(450, 400, -image => $button3, -anchor => 'n
+w', -tags => ['but2']);

$c->bind( $but2, '<Enter>', sub {$c->itemconfigure( $but2, -image => $
+button4); });
$c->bind( $but2, '<Leave>', sub {$c->itemconfigure( $but2, -image => $
+button3); });
$c->bind( $but2, '<ButtonPress>', sub { 
        &disconnect;
        $mw->fontDelete('info_rus'); $mw->fontDelete('ticks'); $mw->fo
+ntDelete('bar_rus'); $mw->fontDelete('dial_rus');
        exit; });
[download]