I have to say I'm not 100% clear on your code ('cos I haven't read anything of it except the nasty big regexp :) but one suggestion does occur to me.

The fields are separated by spaces, right, so why not just split into an array, then you'll be able to get at the array element you want. Something like this:

my @flds = split / /;
$flds[14] = $TOC{$flds[14]};
print "@flds" ;#this is quoted so it's printed with a space between ea
+ch field
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hth,
andy.