if (eval { require "module/that/does/not/exist"; 1 } ) {
   print "loaded module ok\n";
} else {
   print "could not load module: $@\n";
}

##</code><code>##

if (eval { require "module/that/does/not/exist" } ) {
   print "loaded module ok\n";
} else {
   print "could not load module: $@\n";
}