Certainly, you don't really want to do this:

open (OUTFILE, ">@htmlLines") or die("Can't rewrite the HTML file.\n")
+;
[download]

You're using all the contents of the array -- which would appear to be all the text contents of a file -- as the file name. (Try including the same "string" in the error message that reports failure to open the file, so you'll know when the failure is due to a bad file name.)

You seem to have a usable, sensible file name for opening "INFILE", and you should do the similar thing when opening "OUTFILE" -- maybe change the name a bit, so you don't obliterate the original data file, or else rename the original file to something else, first (before you use that file name again for output), to preserve the input data -- this is important when debugging this sort of script.