If I assume you want to use the value to insert a new row, I would go for something like (pseudo code):

# Reset number of tries
$trycount=0;

{ 
  # Increase number of tries
  $trycount++;

  # Make sure we don't try forever
  last if ($trycount > 10)

  # Put last id + 1 in $id
  SELECT MAX(id)+1 FROM table;

  # Try to insert new row and check for errors
  INSERT INTO table (id,col1,coln) VALUES ($id,$col1,$coln);

  # Try again
  redo if (error eq "Unable to insert due to duplicate values");
}

# Handle too many tries
die "Too many tries" if ($trycount > 10);
[download]

The things you need to know is the key (id) of the table and how DBD:ODBC reports a failure to insert because a row is already there (someone else was faster).

/brother t0mas