It's not clear to me from the above whether you have solved your problem or not?

The basic gist of the problem (from reading the error message you posted), is that your code created a db handle in one thread and then attempted to use from another.

Well, its kinda solved... However, this means that I cant have a "global" db connection? What about this situation:

my $dbh = DBI->connect("dbi:mysql:$db:$host", "$db_user", "$db_passwor
+d", {RaiseError => 0, PrintError => 0} ) # We do the error check. May
+be we dont wanna die if error!
                               or errTrap("Cannot connect to the datab
+ase");


threads->create(&dbUpdate()))->join;
threads->create(&anotherThread()))->join;

sub dbUpdate() {

    while(1) {
         do som db stuff when wanted
    }
}

sub anotherThread() {

   do stuff on shared variables that the db uses...

}
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Guess the solution is to have the db obj in the dbUpdate function ONLY...