The code you posted does not neccessarily indicate that Libs::MyPackage is the problem. Look for example at this code:

use Libs::MyPackage;
print "Package included\n";
BEGIN {
    sleep 10;
};
[download]

This will print "Package included" only after 10 seconds. Any <c>use line is equivalent to a BEGIN block, so any other module could cause the same problem, as could any not/slow responding network drive if you're (trying to) loading modules from there. Also, a virus scanner might run wild.