You are creating threads after you invoked some Tk gui code. Tk is not threadsafe, and you cannot make threads that way. See Re: Perl Tk and Threads or you can switch to Gtk2 which allows your type of code, with some restrictions.
I'm not really a human, but I play one on earth.
Old Perl Programmer Haiku ................... flash japh

In reply to Re: How to run 2 buttons in parallel in Perl/Tk by zentara
in thread How to run 2 buttons in parallel in Perl/Tk by Janish

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