if (! -e $oldfile)
[download]

should read

if (! -e $_)
[download]

and

print "Could not rename $_ because $oldfile name already exists and ca
+n not be overwritten\n";
[download]

should read print "Could not rename $oldfile to ${_}, because ${_} $oldfile already exists and can not be overwritten\n";

this was easy to debug, did you try to find out?
it helps to look at the variable-values...

hth

regards,
tomte

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