Also, something's fishy about

This fixed the problem I had with the holes in the fourth field.

The "then" and "else" part are identical.

if ($id eq "") {
    $id=sprintf("%-*s",8,$prev_id);
}
else {
    $id=sprintf("%-*s",8,$prev_id);
}
[download]

is the same thing as

$id=sprintf("%-*s",8,$prev_id);
[download]

I am still getting missing values for the SIC code in the second field

The problem occurs for the first record of every employee except the first employee. That should be easy to debug.