What are you trying to do when you do while(ERROR){if($_ !~/STATUS CODE([0-9A-Za-z].*)VIP CODE/){... }}?There is nothing in $_ (at least not what you are expecting) since you are not reading from the ERROR-filehandle. To do that you must use <ERROR>. Then you read from the ERROR-filehandle, get the next line in $_ and you can test it. Now your regex fails everytime (and the test succeeds because you use !~) and you print the header file again and again.

The easiest way to deal with your program is to make the ERROR-file by hand (just typing the header-line in a text-editor or so) and never, ever write the header to it, just the lines you extracted from the other files.

Sometimes automation just gets in the way.