You can't have run the code you posted:

perl -c xx.pl 
[Thu Sep  3 09:15:03 2020] xx.pl: String found where operator expected
+ at xx.pl line 16, near "$fileto" ) or die ""
[Thu Sep  3 09:15:03 2020] xx.pl:     (Missing operator before " ) or 
+die "?)
[Thu Sep  3 09:15:03 2020] xx.pl: Scalar found where operator expected
+ at xx.pl line 16, near "" ) or die "$!"
[Thu Sep  3 09:15:03 2020] xx.pl:     (Missing operator before $!?)
[Thu Sep  3 09:15:03 2020] xx.pl: String found where operator expected
+ at xx.pl line 16, at end of line
[Thu Sep  3 09:15:03 2020] xx.pl:     (Missing semicolon on previous l
+ine?)
Status: 500
Content-type: text/html

<h1>Software error:</h1>
<pre>syntax error at xx.pl line 16, near &quot;$fileto&quot; ) or die 
+&quot;&quot;
Can't find string terminator '&quot;' anywhere before EOF at xx.pl lin
+e 16.
</pre>
<p>
For help, please send mail to this site's webmaster, giving this error
+ message 
and the time and date of the error.

</p>
[Thu Sep  3 09:15:03 2020] xx.pl: syntax error at xx.pl line 16, near 
+"$fileto" ) or die ""
[Thu Sep  3 09:15:03 2020] xx.pl: Can't find string terminator '"' any
+where before EOF at xx.pl line 16.
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