Try:

use FindBin;
use lib $FindBin::Bin;
use basedat;
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Update - Explanation: use basedat "$Bin/basedat"; is probably not doing what you want because it's just trying to pass the string "$Bin/basedat" to basedat->import() (see use), it's not telling Perl where to actually find the module. To do that, you need to modify @INC, which I'm doing above with FindBin and lib.