Is the perl interpreter located at /usr/local/bin/perl, or /usr/bin/perl, or another location? When you type perl test.pl, you are using the perl interpreter as found in your path; when you type ./test.pl, it is as if you had typed /usr/local/bin/perl test.pl. Depending on the system, one way you might be able to determine the location of your perl interpreter would be to type which perl, which will show you the first location for the perl interpreter as found in your path.

Hope that helps.