First of all, are you sure this code works? perltidy reports that it parses this way:

...
  $count = $dbh->do("INSERT INTO  ques (...) VALUES (...)",
                    undef,
                    $usernamenow,
                    $txtque,
                    ...
           );
...
[download]

I think you want single quotes for the SQL statement and placeholders (?) like this:

  $count = $dbh->do('INSERT INTO ques (...) VALUES (?,?,?,?,...)',
                    undef,
                    $usernamenow,
                    $txtque,
                    ...
           );
[download]

You use of double quotes and string interpolation (i.e. using $usernamenow inside the double-quoted string) will definitely cause you problems.