Well, make sure your file options are correct. I just pasted your code and generated some simple code around it to output to temp.html:

# open TEMP filehandle "temp.html" for appending/writing.
open $TEMP, ">>temp.html" or die "temp.html not created.";

#cut and pasted code
printf $TEMP <<"_ENDOFTEXT_";
#other stuff
<TABLE HEIGHT="100%" CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BO
+RDER="0">
#more stuff
_ENDOFTEXT_

#close TEMP filehandle.
close $TEMP;
[download]

It worked fine, and did not return any invalid hashes or any errors at all. Don't comment on the bad coding practice, I did this in a few seconds. It's more working pseudo-code than anything. I compiled it under Win32 with ActivePerl 5.6 and on Linux using Perl 5.6.0. I didn't try with 5.7.0.