You said you got this error message:

Can't locate MAS::Global in @INC [...]
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The error message indicates that Perl is looking for a file named MAS::Global when you want it to look for a file named MAS/Global.pm.

This happens, like choroba said, when require "MAS::Global"; is used instead of require MAS::Global; or require "MAS/Global.pm";.

$ perl -e'require "MAS::Global";'     # Bad
Can't locate MAS::Global in @INC [...] at -e line 1.

$ perl -e'require MAS::Global;'       # Ok
Can't locate MAS/Global.pm in @INC [...] at -e line 1.

$ perl -e'require "MAS/Global.pm";'   # Ok
Can't locate MAS/Global.pm in @INC [...] at -e line 1.
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So check again, because require "MAS::Global"; or equivalent is definitely used somewhere in your code. The full error message will even say in what file and on what line. Add use Carp::Always; if you need a stack trace.

If you're still unable to find the problem, start by providing the full (unedited) error message.

In case you need it, the following is a portable method of converting a package name to a path for require:

# Equivalent to what `if.pm` uses.
my $require_path = $pkg_name =~ s{::}{/}gr . ".pm";
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