a) It wasn't a wrong parameter...followed the documentation and code seen elsewhere...not that stupid.

b) Originally I was just testing to see if it would even show arguments, as shown in the code provided ($primer3->arguments), though other examples all point to the same line which you provided due to the nature of the program.

However, it seems for some reason there are multiple Primer3.pm files available, one modified from '01 and another in '03. Changing which file was contained within the library for some reason has allowed it to run.

My only error now is "Executable was not found. Do not know where primer3 is!" via:

my $results = $primer3->run;
[download]

Error seen in Primer3.pm:452.