diff --git a/lib/Slic3r.pm b/lib/Slic3r.pm
index 0ba36347cc..9da4779005 100644
--- a/lib/Slic3r.pm
+++ b/lib/Slic3r.pm
@@ -3,7 +3,7 @@ package Slic3r;
 use strict;
 use warnings;
 
-our $VERSION = "0.5.7";
+our $VERSION = "0.5.8-beta";
 
 our $debug = 0;
 sub debugf {
diff --git a/lib/Slic3r/ExtrusionPath.pm b/lib/Slic3r/ExtrusionPath.pm
index a56a210f66..fc69192382 100644
--- a/lib/Slic3r/ExtrusionPath.pm
+++ b/lib/Slic3r/ExtrusionPath.pm
@@ -98,7 +98,7 @@ sub detect_arcs {
     
     # we require at least 3 consecutive segments to form an arc
     CYCLE: while (@points >= 4) {
-        for (my $i = 0; $i <= $#points - 3; $i++) {
+        POINT: for (my $i = 0; $i <= $#points - 3; $i++) {
             my $s1 = Slic3r::Line->new($points[$i],   $points[$i+1]);
             my $s2 = Slic3r::Line->new($points[$i+1], $points[$i+2]);
             my $s3 = Slic3r::Line->new($points[$i+2], $points[$i+3]);
@@ -162,7 +162,7 @@ sub detect_arcs {
                 my $rotation_angle = PI/2 * ($orientation eq 'ccw' ? -1 : 1);
                 my $ray1     = Slic3r::Line->new($s1_mid,   rotate_points($rotation_angle, $s1_mid,   $points[$i+1]));
                 my $last_ray = Slic3r::Line->new($last_mid, rotate_points($rotation_angle, $last_mid, $points[$last_j]));
-                $arc_center = $ray1->intersection($last_ray, 0);
+                $arc_center = $ray1->intersection($last_ray, 0) or next POINT;
             }
             
             my $arc = Slic3r::ExtrusionPath::Arc->new(