That is strange indeed. I kept experimenting and it seems when the argument to do is higher than the version of Perl running on the machine(even by fractions), that same type of error is thrown, where the 'required' version number is the same as the argument to do.

do 5.00504;
print "\n";
print $!, "\n" if $!;
# output: Perl 5.00504 required--this is only version 5.00503, stopped
+ at do.pl line 6.
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Update: While using a number the same as the version of Perl, the only error thrown is:
No such file or directory

do 5.00503;
print "\n";
print $!, "\n" if $!;
# output: No such file or directory
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But it's good to see that a bug has been reported on that.

Amel - f.k.a. - kel