After examining the sample input and output files that Joes emailed to me, as well as some clarified rules, I think that I was actually quite close with my original script. Here's the final final (see below) version: 
#!/usr/local/bin/perl -w

use strict;

$/  = "\n0";   # read in one record at a time
$^I = '.bak';  # modify input files in place, save originals with .bak

my %convert = (
  HEAL => 'Medical',
  HIST => 'Biography', 
  EDUC => 'Educated',
  RESI => 'Resided',
  OCCU => 'Occupation',
);

my $convert_re = join '|', keys %convert;
$convert_re = qr/\b($convert_re)\b/;

while (<>) {
  s/$convert_re/NOTE $convert{$1}:/g;

  if (/^.*SOUR/) {
    s/^1 NAME/1 TITL/m;
    s/^1 NAME/1 TEXT/m;
    s/^1 NAME/2 CONT/mg;
  }
} continue {
  print;
}

[download]
I made two changes. The input record separator is now "\n0", because each section begins with a line starting with 0. (Although this will have each "\n0" read in as the end of the previous record, that doesn't make a difference for our purposes.) In the substitutions for NAME, I added a beginning of line anchor and removed the word 'data' (turns out that bit was just a placeholder for actual data). Also I fixed my typo of TITLE to be TITL (everything is four letters in this format).

Update: Make that four changes. The change of NAME to TITL is only supposed to occur for sections that start 0 @Snnn@ SOUR, not for all sections. And I stupidly forgot the /m modifier on those regexes when I added the anchors. Thanks for the notice of the problems, tachyon! (Notwithstanding the suggestion that I'm reading in one line at a time; I'm actually reading in a block of lines ending with a newline followed by a zero, as I intended.)

In reply to Re: Converting GEDCOM files by chipmunk
in thread Converting GEDCOM files by Joes

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