a) I wouldn't have thought include would work the way you expect it all, returning the content of the file in a way you can assign it to a variable - if it does, fine with me. if not, replace it with e.g.
$Data = file("buddylist.txt");
$Data = implode('', $Data);
b) Without regular expressions you may not get far at all (though I've seen lots of workaraounds for a lot of different tasks from folks who seem to dislike regular expressions). With regular expression it may get tricky to match nested items. Assuming there is not more than one comment per file
$Data = preg_replace("/\{(.*)\}/s", "", $Data);
should work fine even if there are nested {}.