Another reason for this error, if your paths and @INC are right, could be that you are forgetting to return a true value at the end of your package, i.e. your module Da_corsa.pm should be like:

Nope, perl catches that

$ echo package Shoo; sub foo { warn rand }; > Shoo.pm

$ perl -I. -MShoo -e Shoo::foo
Shoo.pm did not return a true value.
BEGIN failed--compilation aborted.
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With the code he posted this new error isn't possible ... so he must not be running the code he posted