Tk is supposed to work when tainting is enabled (I knew this because there is a Tk::tainting() function that is used to skip certain steps when tainting is turned on).

You are lucky in that the first Tk script I tried exhibited the same problem. Going against the advice of saints and savages I quickly decided to jump into the debugger to figure out where the problem really was.

I quickly found and fixed the problem (OK, if you really hate debuggers for debugging, I suggest you tackle this particular problem on your own without using the debugger and see if you can find the problem in 5 minutes like I did -- seriously). The following paragraph tells how to fix the problem but is obscured for those who want to "take the challenge". Simply "download code" or cut'n'paste to get the solution (or just "select" the area and the colors will change so that the text is visible).

In Tk.pm, find "sub TranslateFileName" and insert the
following line as the last line of the "unless" block
(making it line 353 in my copy of Tk.pm):
$Home = ( $Home =~ m#^([-\w/.:,]+)# )  if  Tk::tainting;
[download]

Now if I can just manage to produce and submit a patch. ):

A quick check of:

    #!/usr/bin/perl -wT
    use Tk;
    my $mw=new MainWindow;
    MainLoop;
[download]

And sure-enough, something's tainted. But Tk is unkind enough to tell us what exactly. My first instinct was "Environment" (which it always is with tainting) and this cured it:

    #!/usr/bin/perl -wT
    use Tk;
    %ENV=();
    my $mw=new MainWindow;
    MainLoop;
[download]

Granted, this cure is rather drastic. Now you get to go spelunking and find out what exactly what environment bits that Tk is interested in. In my case, under Win32, it was 2 environment variables that aren't mentioned at all in perlsec. Good luck!