diff --git a/xCAT-buildkit/lib/perl/xCAT/BuildKitUtils.pm b/xCAT-buildkit/lib/perl/xCAT/BuildKitUtils.pm
index 9a0dc30a4..df652727c 100644
--- a/xCAT-buildkit/lib/perl/xCAT/BuildKitUtils.pm
+++ b/xCAT-buildkit/lib/perl/xCAT/BuildKitUtils.pm
@@ -268,6 +268,8 @@ sub testVersion
     for (my $i = 0 ; $i < $len ; $i++)
     {
         # remove any non-numbers on the end
+      if(defined($a1[$i])&&defined($a2[$i]))
+      { 
         my ($d1) = $a1[$i] =~ /^(\d*)/;  
         my ($d2) = $a2[$i] =~ /^(\d*)/;
 
@@ -287,6 +289,7 @@ sub testVersion
             $num1 .= $d1;
             $num2 .= $d2;
         }
+      }
     }
 
     # Remove the leading 0s or perl will interpret the numbers as octal